Why is my inbox always full?

Sep 2, 2021 | Outlook Hints and Tips

This post was prompted by one of my delegates who was having exactly this issue and didn’t know why!! 

Have you ever had a message to say your mailbox is full?  You clear out loads of emails from your inbox and within a few days the same message reappears?  How can that happen?  There are a number of things that need to be understood with regards to this issue and how to solve the problem.  This article is predominately aimed at Outlook users but most of the principles are the same regardless of which emailing platform you are using. 

Sent items 

Every time an email is sent out a copy of that email is stored in the sent items folder.  This is included in the capacity of the mailbox so old items need to be regularly deleted in the same way you would do with your inbox. 

Deleted Items 

Deleted items also affect the capacity of the mailbox so also need to be regularly cleared out.  Depending on your settings this may be done automatically when you close down Outlook or after a certain number of days or may need to be done manually. 


It is a common misconception that emails filed away in folders do not affect the capacity of the mailbox but they do!!  Therefore these folders should also be tidied up periodically too. 


Another option is to setup automatic archiving on all or some of the folders you are working with.  When folders are archived the emails in them are still able to be accessed from with Outlook.  They look the same and operate the same as normal emails but they don’t take up any space in the mailbox.  The archived folders are viewed within an overarching folder called archive with the same filing structure as within the normal emails and still viewed within the mailbox.  You may consider that emails older than 6 months for example are less likely to be relevant so removing these from your mailbox storage could be totally acceptable. 

File attachments 

File attachments are often overlooked in the impact they have on your storage quota.  The size of the emails containing them can often be 10 times the size of an email containing text alone but can be much, much larger.  If you can save the file attachment in your normal filing system then delete the email (not forgetting to delete the deleted item too) then large volumes of memory can be saved.  In Outlook there is even an option to search on the email size using the advanced find option or even create a search folder to continually search for large emails which can help you pinpoint where you should be concentrating your efforts. 

Mailbox capacity 

The maximum size of your mailbox will be different with different packages and can also be different between different companies.   For free mailing software this is normally quite low.  For paid for versions much larger.  However with paid software different IT departments will set  different restrictions depending on how much capacity they want to give people and can even be adjusted on an individual basis if the job role requires it.  This option may not be something you can control but having a word with your IT team may enable a change to the capacity to be made. 

So try out some, or all, of these suggestions to prevent the dreaded “Your mailbox if full” message from popping up again. 


Further Reading

If you’ve enjoyed reading about the different ways to keep your inbox organised, there’s some other blogs below that you might find useful:

Want to learn more about Microsoft Outlook? Then email lara@laramellortraining.co.uk to discuss how I can help or have a look at the Microsoft Outlook Courses I run.