SPO version history + huge PST files + slow internet + maxed storage

Super Contributor

I had a client run out of SPO space last week. After some digging, we realized that some users had uploaded PST files (between 1.5 and 2.6 GB each). For the next 12-32 hours, SPO created a new version of the file every 15 minutes, to the tune of 1.5GB, 2.6GB, etc., for each version. They do not have the best bandwidth and I'm wondering if that's what's coming into play here. 


I've read before that the versions are only the delta, but in the case of the PST file versions, they all appeared to be the same size.


Has anyone seen this before? Any words of wisdom here (other than using online archive instead of PSTs)?

7 Replies

Hi @Kelly_Edinger ,


Could you move the PST file to a document library with no versioning?


I hope this helps.



Hi @Norman Young 

Thanks for jumping on the thread! Yes, I could probably move it somewhere else without versioning.  I guess I'm trying to figure out how to best advise people that want to store large files. We tell them it can be up to 15GB, but if SPO is going to create a version every 15 minutes while it uploads, that's an issue. Do we tell them they can either have large files OR version history if they don't want to purchase extra storage. I never expected to see so many files with new versions every 15 minutes.

Splitting the PST file by year might reduce some of the contention for end-users. I'm out of my league when it comes to Outlook but large active files will have more contention than smaller active files. Splitting combined with no versions should buy back some performance.
best response confirmed by Kelly_Edinger (Super Contributor)
SharePoint isn't making the versions. Them having it open in outlook is making updates to the file constantly. The first thing I do is restrict *.pst files from OneDrive and SharePoint because they are a plague.

Moving them to archive or having a 3rd party client backup tool handle pst's is the only way to go. Another library won't work either since soon as Outlook touches the pst it's going to be modified and re-uploaded every single time if you're using sync.

The only time you get delta backups with files in SPO is office online documents, everything else will be full versions for every change / version.

@Kelly_Edinger I have the same issue but just compounded due to compliance retention policy.  I am stuck and unable to delete the old versions.  In our case just 2 pst files have over 4 Tb or space.  Anyone know any quick way to delete these versions even though they are retained due to retention/hold policy?

Not without adding that particular user/site to the exclude list in the retention policy, letting it process, then removing it and adding back, that's your only way, but now that they updated retention policy, the preservation library doesn't immediately go away, think it won't for 30 days or so. Not sure if you can manual delete the item out of that library once it's excluded, might be able to modify it once it's excluded then reapply possibly. But outside of exclusion you can't do anything about it.

@Chris Webb Chris thank you for the response.  I have started the process to move the file to the users' local drive and delete this.  Will update this thread on the progress.