Teams won't allow me to attach a file to an assignment

H Vardy (KES Staff) 10

I get an error message when I try to attach a document to a Teams assignment. I was able to do this before. I have tried in both the browser and the app and also tried uploading the file locally, from One Drive and from Teams in the files section of the channel.

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Matt Grimley 0 Reputation points

2025-09-11T11:48:53.02+00:00

I'm getting the same issue in two different schools in new teams created using the EDU_Class template. The same command and policy has been used to create teams over several years without this issue:
New-Team -DisplayName "(TEST TEAM)" -Description 'Test team (0925)' -MailNickName "25TestTeam" -Template EDU_Class -Owner '******@ourtennant.county.sch.uk'
Our staff all use school accounts on the organisation tenant.

Error when uploading pptx files as teacher and i can replicate (as global admin) issue uploading a tiny jpg file to a new test team this morning.

Problem can be replicated both on Windows 10 and 11, using Teams Web (in edge) and Teams Desktop App.

Problem occurs when uploading a file or attaching "Cloud Files" from OneDrive.

Looking at the SharePoint for the team, it lacks a "Class Files" and a "Student Work" directory. (manually creating them doesn't work).

I have a ticket open with Microsoft, but I'm not hopeful of a quick response.
c h 0 Reputation points

2025-09-26T07:21:58.93+00:00

This happened to me. Suddenly in all my Teams meetings with different clients I am unable to attach any PDFs or additional files of any type. None are anywhere close to the size limits. Last week, it was possible and now this week everything changed. Is this was a Microsoft action, then stop trying to "help" us.

The account is a company profile, not a MS/hotmail one.
Using Windows 10
Trying to send local files
Occurs every time

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