Azure Windows VDI Became Slow and Teams Is Unusable—What Should I Check?

There is not enough information to identify one cause yet. Useful details include the VM SKU and number of session hosts, concurrent user count, CPU and memory utilization, whether all users or only some are affected, connection method, network path, and whether the hosts are domain joined or cloud only. Compare a healthy and unhealthy session, and review recent image, Teams, or Azure changes.

Start by separating the two problems. If the entire desktop is slow, check CPU, memory, disk I/O, network round-trip latency, and—if you use burstable VM sizes—remaining CPU burst credits during an active incident. If only Teams is affected, verify that Teams media optimization for Azure Virtual Desktop is enabled and working. Also check whether the host image, Teams version, or networking configuration changed around the time the issue started.

Burstable B-series session hosts can look fine until they run out of CPU credits. After that, performance may drop sharply, especially with multiple users. Check the VM metrics and consider moving to a non-burstable SKU or resizing the hosts if the credits are depleted regularly.