Dear Tom,
Unfortunately, as a forum moderator, I am not able to inspect your device or Teams client to diagnose this directly. My role here is limited to general guidance you can apply from your side.
Before anything else, could you clarify what you mean by a particular Team in People? Does the freeze happen when opening a contact group in the People app, or when selecting an actual Team? It would also help to know whether this affects one user or several, and which Teams version and operating system are involved.
That said, what you describe closely matches an issue several users are currently reporting, where Teams freezes once the contacts list has fully loaded. Reports point to it starting after Teams build 26198.304.4946.9672, and it appears to affect users who have categories applied to their contacts.
In the meantime, these are worth trying:
- Try Teams in Firefox, users have reported that Firefox works normally while the desktop client and Edge both freeze, which points to the rendering path rather than your account or the service.
- Reset the Teams app under Settings > Apps > Installed apps > Microsoft Teams > Advanced options > Reset. Be aware this is temporary, as users report the freeze returns after the next restart or Teams update.
- If the contacts have categories applied, try viewing the list without them to see whether that avoids the freeze.
Separately, I can share that Microsoft is aware of a related issue where some users may experience latency when viewing their Teams contact lists. A fix has been identified and is rolling out through the Teams service update rings, with general availability expected around the first week of September. Please note this addresses the loading delay rather than the freeze itself, so it may or may not resolve what you are seeing.
I would also suggest having your admin raise a support case from the Microsoft 365 admin center so it is formally logged against your tenant: Get support - Microsoft 365 admin. If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support
For reference, here is the ongoing thread: Teams freezes up when scrolling with mouse in contact people list - Microsoft Q&A
I hope this helps. Looking forward to your reply.
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