SharePoint Online removing file extensions when uploaded

Question

Weird issue with SharePoint - it's removing the file type extension (.pdf, .docx. xls etc) when items are uploaded into a document library via drag & drop. This renders the file un-openable, but if you download it and put the file extension back in manually then the file will open. So it isn't corrupting files, just stripping away the extension.

Uploading via the Upload button works fine, no problems. This seems isolated to uploading via drag & drop.

Anyone experienced this or know of some suggestions for a fix? Have tried the usual log out/in, cache clear etc. Using Edge on MacOS predominantly but also happens in Safari.

Answer 1

Dear EndOfAnError,

Thank you for the detailed reply.

You mentioned "All sites in our tenant are affected", and your colleagues have the same problem on their Mac devices, the problem may be related to the SharePoint backend.

Given this situation, more resources need to be involved in the issue in your environment. I suggest you contact the administrator in your company if you aren’t the administrator and follow the steps in the article to open a ticket, this is the most efficient way to fix the issue in your environment. Because the support team there will have specific diagnostic tools that can help troubleshoot this issue further, their support will continue to investigate this issue and provide suggestions for you.

Appreciate your understanding.

Sincerely,

Jazlyn | Microsoft Community Moderator

Answer 2

Hi Jazlyn,

Thanks for your response, please see answers to your questions below.

1. There are 19 of us in the business, I've asked 8 of them to test and it's happening to all 8.
2. All sites in our tenant are affected. Nothing has changed recently in terms of permissions or any other backend setting.
3. This doesn't happen with OneDrive. It also doesn't happen if I drag & drop upload a file on my Windows PC, only on the Macs.

Many thanks

Answer 3

Dear EndOfAnError,

Good day! Thank you for posting your query in our community.

Based on your description, when you try to upload files to SharePoint site via drag & drop, file extensions disappeared and you can't open those files. I tested it on my side, there was no problem.

To narrow down the scope of the issue, could you please provide more information for me?

1. Do your colleagues have the same error on their side?
2. Does the problem happen on all the sites, or only this specific site?
3. Does the problem happen on your personal OneDrive in the browser as well?

Appreciate your cooperation in advance.

Sincerely,

Jazlyn | Microsoft Community Moderator