Hi @IBN
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Based on my knowledge, there are many factors that can cause Teams client running slowly, so it recommends you check these steps to see if it works in your environment
1)Open too many application at the same time. Please close the applications you don't need in your device.
2)Network issue. Please check if you have enough network bandwidth and change another network connections.
3)Teams client issue. Please make sure you have the latest version of Teams client and try to clear Teams client cache file, restart Teams client.
Also, to narrow down this issue, you may try to perform a clean boot in Windows and check if there is the same results.
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