If an email account takes up a lot of storage space or can no longer receive new messages, you can check the usage directly in cPanel. With the feature Email storage usage Furthermore, it can be determined in which mail folders a particularly large number or large size of messages are stored.
In this guide, we will show you step by step how to check the storage usage of an email account in CURIAWEB, find large mail folders, and selectively clean up messages you no longer need.
Important: Do not delete emails simply because a mailbox is taking up a lot of storage. First, check which folders are using the storage and whether the messages contained in them are still needed.
Why can an email inbox become full? #
When using IMAP, emails are normally stored on the mail server and synchronized with the devices used.
Over months or years, large amounts of messages and attachments can accumulate as a result.
Not only the inbox requires storage. Other mail folders can also account for a significant portion of the usage.
This includes, for example:
- Sent
- Drafts
- Recycle Bin
- Spam
- Archive
- self-created subfolders
Especially messages with large attachments can significantly increase memory usage.
What happens when a mailbox reaches its limit? #
If a storage limit is set for an email account and this limit is reached, further delivery of messages may be impaired.
Senders can then receive an error message depending on the specific email process.
If a delivery fails due to a quota or a full mailbox, you should therefore first check the actual storage usage of the affected account.
Briefly explained: A full mailbox is not a spam filter, password, or DNS issue. Before changing other settings, first check your storage usage and storage limit.
1. Open Email Accounts in cPanel #
Log in to your CURIAWEB cPanel.
Scroll to the section on the homepage Email and open Email accounts.
Here you can find the configured email accounts of your hosting account.
2. Search for affected email account #
Find the mailbox whose storage consumption you want to check.
For example:
info@deine-domain.ch
With multiple domains, make sure you actually select the correct account.
3. Check account storage usage #
In the account management, depending on the cPanel view, you can see information about the used or available storage of the email account.
Check how much storage is currently used and what the storage limit is for the account.
For example, an account can use a lot of storage without having reached its limit yet. Conversely, a smaller account limit can result in a mailbox being full despite a comparatively small absolute amount of data.
Important: Distinguish between allocated memory and the one set for the email account Storage limit.
4. Check the e-mail account storage limit #
If necessary, open the management function of the relevant email account.
There you can check which storage limit has been set up for the account and – as far as your hosting account allows – adjust the setting.
Do not automatically increase a limit with every memory issue.
For example, if several gigabytes of old spam, trash, or unnecessary attachment data are stored, cleaning it up is often more sensible than permanently increasing the limit.
We show how to manage an existing account at Manage or delete email account in cPanel.
5. Open „Email storage usage“ #
For a more detailed analysis, you return to the cPanel home page.
Open in the section Email the function Email storage usage.
With this tool, you can analyze how the used storage of an email account is distributed across its individual mail folders.
6. Select desired email account #
Select the mailbox you want to examine.
For example:
info@deine-domain.ch
cPanel then analyzes the mailboxes and folders belonging to this account.
7. Analyze mail folders by storage usage #
The overview shows your existing mail folders and their storage usage.
This allows you to see where a particularly large amount of data has accumulated.
For example, a mailbox may have a relatively small inbox, while the sent items folder has grown very large.
Practical Tip: When cleaning up, focus on the largest folders first. That is usually the quickest way to see where storage is actually being used.
The „Sent“ folder is often underestimated #
When their mailbox is full, many users first look in the inbox.
However, the sent items folder can require just as much or even more storage space.
If you regularly send large PDF files, images, quotes, or other attachments, copies of these messages are often saved in the folder, depending on your email client and its configuration. Sent Saved.
Therefore, check this folder as well.
Check spam folder #
If detected spam messages are stored in a separate folder, a larger amount of data can also accumulate there over time.
Check your spam folder regularly and delete messages you no longer need.
We explain how to configure spam processing in cPanel at Configure spam filter in cPanel.
Recycle bin also requires storage space #
Moving an email to the trash does not necessarily mean that its data has been immediately removed from the server.
As long as the message is still stored in the trash, it can continue to take up storage space.
Therefore, when you no longer need messages at all, also check the trash and empty it if necessary.
Important: Check the content before final deletion. An emptied trash bin is not the same as merely moving a message from the inbox.
Don't forget the archives and your own folders #
Many users create their own folder structures over years.
For example:
Customers
Invoices
Projects
Archive 2025
With IMAP usage, these folders are also normally located on the mail server and therefore count towards the account's storage allocation.
The term „archive“ does not mean that the emails stored in it have been automatically offloaded from the server.
8. Open clean-up function for a folder #
In the overview Email storage usage can you open the available management or cleanup function for a selected mail folder.
cPanel can offer various criteria based on which messages can be deleted.
Which specific options are displayed depends on the cPanel version and server configuration used.
Attention: A cleanup via cPanel can affect many messages at once. Carefully check the selected criterion before executing the operation.
9. Select cleansing criterion #
Depending on the available space, messages can be selected for cleanup based on their age or other criteria, for example.
Choose only one rule whose effects you can understand.
A blanket deletion of large volumes of old emails can be problematic if it includes messages that are still needed for business or legal purposes.
Old emails are not automatically unimportant #
The age of a message says nothing about whether it is still needed.
For example, an email that is several years old can contain an agreement, invoice, customer communication, or other relevant information.
Therefore, do not use age as the sole decision criterion for deleting business messages.
Practical Tip: If old emails are still needed, check for a suitable archiving method before removing them from the server.
Confirm cleanup #
If you are sure that the selected messages are no longer needed, you can run the cleanup.
Check again beforehand:
- the correct email account
- the correct mail folder
- the selected deletion criterion
- whether required messages were backed up or archived
Confirm the process only afterwards.
Check memory allocation again. #
Check the disk space usage again after the cleanup.
This allows you to determine whether the desired amount of data has actually been reduced.
Depending on the system, it may take a moment for updated memory values to be fully displayed.
Free up storage space via Webmail #
You don't necessarily have to remove messages via the cPanel cleanup function.
If you want to see exactly which emails are being deleted, webmail can be clearer for a manual cleanup.
There, for example, you can check messages by date, sender, or other criteria and delete them selectively.
Don't forget to empty the recycle bin if necessary afterward.
Free up storage space using an IMAP mail client #
If your email account is set up via IMAP in an email program, changes are normally synchronized with the server.
If you delete a message in the IMAP mailbox, this generally also affects the server-side inventory.
However, the exact behavior may depend on the mail client, folder configuration, and deletion options.
Attention: With IMAP, your mail program is not a completely independent copy of the mailbox. If you delete a synchronized message and the deletion is synchronized with the server, it can also disappear on other connected devices.
Differentiate between IMAP and local archiving #
A folder within your IMAP account usually remains on the mail server.
For example, if you have a subfolder in your email program:
Archive
if you create within the IMAP account and move messages there, you normally do not save any server-side storage by doing so.
You merely moved the messages from one server folder to another server folder.
Local folders can work differently #
Many email programs also offer local folders or local archives, the data of which is stored on the computer being used.
If messages are deliberately moved from the IMAP account to such a local area and subsequently removed from the server, this can free up storage space on the mail server.
However, this procedure has consequences.
Afterwards, the messages may only be located on this computer or within its local database.
Important: If you archive emails locally, you need a reliable data backup of that computer or the local mail archive. Otherwise, a malfunction or data loss could also destroy your only archive.
Do not confuse POP3 and IMAP #
With IMAP, the mailbox remains fundamentally server-oriented and is synchronized between the server and devices.
POP3 works differently and can download messages depending on the configuration and, if necessary, remove them from the server after a certain time.
That is why, before a major cleanup, you should know how the email account in question is set up on your devices.
POP3 does not automatically mean „deleted from the server“ #
Even with POP3, an email client can be configured so that copies of the messages remain on the server.
In this case, the server-side utilization continues to grow despite regular retrieval.
Therefore, do not rely solely on an account being set up via POP3. Check the actual storage usage in cPanel.
Large attachments as storage hogs #
Emails with images, PDFs, presentations, videos, or other large attachments require correspondingly more storage space.
Particularly the regular sending and receiving of large files can cause both the inbox and the sent items folder to grow quickly.
If a mailbox requires an unusually large amount of storage space, it is therefore worthwhile to search for particularly large messages.
Save attachment and delete email? #
If you save an important attachment outside of your mailbox and then want to delete the corresponding email, you should keep in mind that the message may contain additional information.
This includes, for example, sender, recipient, date, accompanying text, and the context in which a file was sent.
Therefore, consciously decide whether only the attachment or the entire communication needs to be archived.
consider business record retention #
In business email communication, legal, contractual, or internal retention obligations can play a role.
Which messages need to be kept for how long depends on the specific content and the requirements that apply to your company.
Important: Do not delete business-relevant messages solely for reasons of space if you have not clarified whether they still need to be retained.
Increase storage limit or delete emails? #
Both can make sense depending on the situation.
If the mailbox contains exclusively required current and archive-obligatory messages, additional storage may be required.
If, on the other hand, a large part of it consists of years of accumulated spam, trash contents, unnecessary copies, or attachments that are no longer needed, cleanup is the better first step.
Therefore, the crucial question is not just „How full is the inbox?“, but why it requires so much memory.
Difference between hosting storage and mailbox limit #
A single email account can have its own storage limit. At the same time, emails, website files, databases, and other data share the available storage of the hosting account.
A very large mailbox can therefore also contribute to the total storage allocation of the hosting package.
Increasing the limit of a single email account does not create additional physical storage space in the hosting account.
Briefly explained: A higher mailbox limit simply means that this account is allowed to use more storage. It does not automatically increase the total available storage of your hosting package.
Examine multiple large mailboxes #
When total hosting storage is running low, you shouldn't just look at the obviously largest mailbox.
Several medium-sized accounts can also cause significant storage consumption together.
Therefore, use the overview to systematically check email usage.
Mailbox is full and cannot receive messages #
When a mailbox has reached its storage limit, you should first free up sufficient storage space or adjust the limit—if sensible and available.
Then test the reception with a new message from an external address.
Use a clear subject line for this, for example:
Test after memory cleanup
Then check if the message arrives.
Messages are still missing after storage cleanup #
If sufficient storage is available, but a specific message still does not arrive, you should not continue deleting emails at random.
Investigate the delivery method instead.
With Track email delivery in cPanel Can you check if the message in question has been processed and if there is an error message?.
Cleanup and email filter #
When messages are regularly sorted into specific folders, these folders can grow unnoticed due to filters.
Therefore, in the case of unusually large subfolders, also check whether automatic filter rules are moving messages there.
We show how you can check such rules at Create and manage email filters in cPanel.
Also consider global filters #
Global filters can also influence how incoming messages are processed.
If you cannot understand why certain mail folders keep growing, you should therefore also check the global rules if necessary.
We explain the configuration at Using Global Email Filters in cPanel.
Spam folder is growing unusually fast #
If the spam folder in particular is growing very quickly, you should also check whether your domain is unnecessarily accepting messages to random non-existent recipients.
An active catch-all configuration can significantly increase the volume of spam to be processed.
We show you how to check this under Default Address in cPanel: Catch-All and Unknown Recipients.
Do not randomly delete mail files in the file manager #
Email data is technically stored within the directory structure of the hosting account. Nevertheless, for normal mailbox cleanup, you should not simply delete mail files via the cPanel file manager.
Use the designated email functions, webmail, or a correctly configured mail program for this.
Attention: Manual deletion of unknown files within the mail directory structure can corrupt mailbox data or lead to inconsistent states.
Do not delete email account to free up storage #
Deleting an entire email account is not a normal method for mailbox cleanup.
Removing an account may affect its server-stored emails.
If you only want to free up memory, selectively clean up the messages that are no longer needed instead.
Back up before major deletion operations #
If you want to remove large amounts of older emails and are not sure whether they will be needed later, you should create a suitable backup or archive before deleting them.
Then check whether the backed-up data can actually be opened or used again.
A backup whose restoration has never been tested should not be lightly considered as the sole copy of important business communication.
Do not refill storage immediately after cleaning #
If a mailbox regularly reaches its limit, you should monitor the cause after the initial cleanup.
Check the storage usage again after a few weeks, for example.
If the account is growing unusually fast, check which folders are responsible.
This is how you can tell whether it is normal email volume, large attachments, spam, or an unfavorable archiving strategy.
Regular inspection instead of emergency repair #
It is much more pleasant to check a mailbox occasionally than to react only when no new messages can be delivered.
Therefore, for heavily used business accounts, you should check the storage usage at reasonable intervals.
Practical Tip: If an important mailbox is permanently at 90 to 100 percent of its limit, that is not a good operational strategy. Clean it up or plan for additional storage before delivery is impaired.
Best practices for a full mailbox #
- Open Email -> Email accounts and check occupancy and limit.
- Open Email → Email storage usage.
- Select the affected account.
- Identify the largest mail folders.
- Check Sent, Spam, Trash and Archive in particular.
- Save any messages that are still needed before performing a major cleanup, if necessary.
- Only remove data that is actually no longer needed.
- Empty the recycle bin if necessary.
- Then check the new memory allocation.
- Send an external test email and check the reception.
When should you contact support? #
If cPanel shows unusually high memory usage, but you cannot find the data causing it, a more detailed analysis may be useful.
For troubleshooting, the following information is particularly helpful:
- affected email account
- displayed storage capacity
- set storage limit
- which folders are displayed as particularly large
- whether IMAP or POP3 is used
- whether delivery errors are currently occurring
- if applicable, the complete error message
Do not share any email or cPanel passwords as part of the normal error description.
Summary #
You can check the storage usage of an email account via Email -> Email accounts check. A detailed breakdown by mail folder can be found under Email → Email storage usage.
When your mailbox is full, don't just check the inbox. Sent messages, spam, trash, archives, and custom IMAP folders can also take up a significant amount of storage.
Target messages selectively and back up important data before major deletions. With IMAP, changes are synchronized with the server; therefore, a folder named „Archive“ within the IMAP account usually does not save any server-side storage.
Increasing a mailbox limit can make sense if the stored messages are actually needed. However, it does not replace sensible cleanup and does not automatically increase the total available storage of the hosting account.
If delivery issues persist after a cleanup, investigate the specific mail path using cPanel Track Delivery instead of deleting further messages on suspicion.
