Why Cleaning Out the Teams Cache Sometimes Helps to Fix Clients

The Art of Performance Improvement

Mark Longton of the Microsoft Teams development group discussed some techniques Microsoft uses to improve the performance of Teams in a January 28 blog. He covers analysis of performance during code development, tools used for analysis, and the creation of debugging and monitoring tools. Finally, he looks at how Microsoft identifies strategic improvements they want to make in specific elements of the Teams client. The text explains that helping Teams to lose an unfortunate reputation for sluggish performance is an ongoing, persistent, and detailed-oriented task.

A response to the post raises the issue of memory consumption, reporting a Teams client taking 1.1 GB RAM. I haven’t seen such a large amount of memory reported for a while, probably not since Microsoft made some changes to Teams memory management in mid-2020. As I write this article, Teams occupies 501 MB RAM on my 16 GB Surface Book 2, which is after switching several times between different tenants to perform a variety of tasks. (12 hours later, Teams occupied 744 MB…)

Clear the Teams Cache

However, I rebooted my PC earlier today, so it’s less likely that the Teams cache of resources stored in memory has accumulated much debris. Over time, the cache can expand to hold data that isn’t used, not required, or corrupt. The solution is to “clear the cache,” or wipe and restart. Like signing out and back into Teams, it’s one of the go-to universal solutions for many odd Teams problems rooted in hard experience of helping end users cope with problems they have with Teams clients.

According to Mark Longton, signing out and back in again is enough to clear the Teams cache. This certainly seems like it should be the case because the cache is an in-memory structure and there’s no reason why Teams should keep data in memory after a user signs out.

However, as evident in this advice from Michigan State University, some support organizations go further and recommend that users of the Teams desktop client for Windows delete the contents of the cache folder in %appdata%\Microsoft\Teams plus a bunch of other folders. The logic appears to be that removing everything Teams downloads to store on the local workstation stops any lingering corruption finding its way back into the Teams cache. The next time the user signs into Teams, the client downloads the data from the cloud to rebuild the files.

Steps to Fix Problems

If someone experiences a problem with the Teams for Windows client, a phased approach is:

Sign out, wait a moment, and then sign back into the client. Sign out can be done from the taskbar (Figure 1) or by clicking the user photo in the title bar and selecting the sign out option. Apart from anything else, signing back in will ensure that access tokens and multi-factor authentication are not expired.

If the problem doesn’t go away, check the web client to see if the same problem exists there. If it doesn’t, the issue is with the desktop client, so go ahead and sign out and then remove local cache files as described above. Before you sign out, use the Collect support files option (available by right-clicking the Teams icon in the system tray – Figure 2) to capture information that Microsoft support might need to resolve problems you can’t fix.

The Great Hope of Teams 2.0

It’s no secret that Microsoft is working on an implementation of the Teams enterprise client based on a new architecture (Teams 2.0). The Teams chat client now available in Windows 11 uses the new architecture, but clearly it takes much more development effort to create a client supporting all the features available in the current enterprise client. Better performance and a reduced memory footprint are two advantages cited for the new architecture. Let’s hope we’ll see the Teams 2.0 enterprise client soon, and that the days of needing to clear cache are left behind. Then again, a new client based on a new architecture will likely bring a bunch of new performance and troubleshooting issues for administrators to consider.

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