SharePoint Modifies Files on its Own

Question

How do I stop SharePoint from modifying files on its own, even when they're never opened? I'd like to preserve the integrity of some legacy data I want to upload to a SharePoint document library. I can't be having SharePoint going through and making modifications to old files on its own.

I've noticed this with HTML, .MSG, and Office files. SharePoint adds a UUID or other metadata to files once uploaded, thereby changing the files and their file sizes. I haven't really found any clear documentation of what's happening, but it appears it's what they call "document property promotion and demotion". If anyone at Microsoft is reading, this is really something that should be well documented and easy to turn off. It renders SharePoint unusable to anyone who requires data integrity or ever wants to use a checksum to compare files.

The workaround mentioned occasionally is setting ParserEnabled to false. I've read that that's not possible on SharePoint Online, but this articlementions another way to turn it off - setting ParserDisabled to true instead (lol). Have any of you ever done this with SharePoint in Microsoft 365? If you have done it, does it create any issues? Have you checked if this actually prevents SharePoint from modifying files and preserves data integrity in all files? I'd like to hear from authoritative source how I can be certain I'm preserving the integrity of data uploaded to SharePoint.

Relevant links

• SuperUser: Why is OneDrive changing the size of files?
• Mike Smith's Tech Training Notes: SharePoint Changes Files as they are Uploaded (2010)
• Microsoft Community: Files are different sizes when stored in OneDrive
• Microsoft TechNet: File size difference when I download the MS office files from SharePoint. (2011)
• Reddit: SharePoint Modifies Files on its Own

Answer 1

Hi L20,

Sorry for the inconvenience that happens to you.

According to your description, I have tested on my side and I can reproduce the same situation. After searching, this situation is indeed not mentioned in the references, and I am afraid it is by design. It seems you have already posted a suggestion in our UserVoice community. If not, I would like to suggest you vote for this suggestion. It’s the platform for us to hear your voice and improve our products.

Also, for your concerns, it does change file sizes. This is a problem for those who may reply on file size to ensure document integrity. Based on my search, I haven’t found any existing PowerShell commands to prevent this behavior.  Since we help members about out of box features questions in the community, for coding PowerShell commands to prevent SharePoint from adding metadata to uploaded files, we have a specific channel Microsoft Q & A Community coping with PowerShell commands questions, I suggest you post a new thread there for expert help.

Sorry for that our category may have limited resources on checking on the issue further.

Appreciate your patience and understanding.

Regards,

George