What is the limit of pst files that you can open in outlook 365?

Question

Hi,

I have one user who created a lot of archives and he wanted to open all of them in outlook.
I would like to know if there is a limit to how many pst files one can open in outlook 365.
if there is, what is the limit?

Thanks

Answer 1

The default maximum file size for a PST file in the Outlook 365 client is 50GB.

I wouldn't recommend opening them when starting the outlook client as it will slow things down - consider an email archiving solution or an Exchange Online/Office 365/Microsoft 365 Plan that has unlimited mailbox/archive mailbox storage and get the user to import the mail back into their mailbox.

Answer 2

Hi @Anonymous ,

Welcome to our forum!

Agree with stevenhodson. The overall size of .pst and .ost files has a preconfigured limit of 50 GB. As for the number of files you mentioned, I haven't found any official documents to introduce this, and I think it's incalculable. It still depends on the size of the files themselves.

For more information about it, please refer to: The file size limits of .pst and .ost files are larger in Outlook 2010 and Outlook 2013.

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Answer 3

In Outlook 365, there is a limit to how many PST files can be opened at the same time. The maximum number of PST files that can be opened in Outlook 365 is 15. This means that if you have multiple archives and want to open all of them in Outlook, they can open up to 15 PST files simultaneously.

Please note that this limit of 15 PST files specifically applies to Outlook 365. Other versions of Outlook may have different limits. Moreover, if a large number of PST files are opened at once, it may affect the performance of Outlook.

If you need to access more than 15 PST files in Outlook 365, it is advisable to consider consolidating or merging some of the PST files to reduce the number of open files. This can help maintain optimal performance and improve usability in Outlook 365.