Outlook Error - The message store has reached its maximum size

Question

Hi,

Got a user who has full delegate permissions on a users mailbox and whenever they try to delete or change items in their mailbox/calendar it comes up with this message:

They have no issues with other peoples mailboxes they are delegates off just this one specific person, also the user themselves have no issues with their mailbox just the delegates. Two delegates are having the exact same issue for this user. We have tried OWA and the delegates can make changes on there no problem just when they are using Outlook 365?

Hope this makes sense and any help would be appreciated.

Thanks

Answer 1

If your Outlook is showing error of “The message store has reached its maximum size” then I must say the size of PST file exceeded. There will be on method that used to repair the PST file when it gets corrupted due to its large size.

Outlook file definitely got corrupted due to its large size, no user wants to lose its valuable data that saves in Outlook. To overcome this situation, Microsoft provides an inbuilt tool i.e ScanPST .exe However, this method can only resolve the basic flaws of the PST file. It cannot fix the highly damaged PST file.

To overcome the situation of corrupted PST file, you need any alternative advanced tool that can fix corrupt PST file. I can suggest you to go through this Video, it helps you to resolve corruption of PST:

https://www.youtube.com/watch?v=AILCu8gmmt8

Answer 2

Hi @Fayraz Hussain ,

Welcome to our forum!

Can the oner of the mailbox instead of the two delegates delete or change items?

According to the error you provide, please check if the size of the mailbox is too large.(File>Info>Tools or refer to: What’s the size of my mailbox)

If the mailbox is indeed to large, do you turn on the Cached Exchange Mode? If so, it's suggested that you could change the offline settings to reduce the downloaded emails by moving the slider to a less months.

In addition, it's suggested that you could try to clean up items to reduce mailbox size in Outlook client. For more information, please refer to the following article: Reduce the size of your mailbox and Outlook Data Files (.pst and .ost). As far as I know, exporting mail to backup is also a good way to reduce the mail size. For more information, please refer to: Export or backup email, contacts, and calendar to an Outlook .pst file.

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

---

Answer 3

Hi,

Thanks for the responses.

The owner of the mail box can make changes without the error it is only the delegates who are having issues and the delegates can make changes in OWA but not using their Outlook 365 desktop app.

Yes we are using cached exchange mode for peoples mailbox but when on shared or delegated mailboxes we are not and just using the online method in Outlook 365.

The owner of the mailbox when looking on his machine no PST files are being used and the OST file is 16.5GB.

Thanks