Teams on a Mac: two apps, two caches, and one of them is dead weight

Teams is the clearest example of a pattern worth knowing generally: when a vendor rewrites an app, the old app's data usually stays on disk. If your Mac has been through both the classic Teams and the newer one, you are storing two complete sets of caches and neither knows about the other.

Find both sets

du -sh ~/Library/Application\ Support/Microsoft/Teams \
  ~/Library/Containers/com.microsoft.teams* \
  ~/Library/Group\ Containers/*Teams* 2>/dev/null | sort -h

Whichever of those paths exists on your Mac, read the sizes rather than the names. The important question is which one has been written to recently, and that is what the next section answers.

Telling live data from leftovers

Sort by modification date rather than guessing from folder names:

ls -lt ~/Library/Application\ Support/Microsoft/ 2>/dev/null | head

A folder last modified a year ago belongs to a version you no longer run. That is the one to remove. A folder modified today is the app you use, and clearing it is a cache decision rather than a cleanup decision.

What is safe to clear in the live one

• Cache and Code Cache. Disposable. Rebuilt on next launch.
• Service Worker. Disposable, resyncs.
• Logs and diagnostics. Safe, and usually small enough not to matter.
• Local Storage and IndexedDB. These hold your session. Clearing them means signing in again.

Quit Teams entirely before touching any of it, including from the menu bar icon if it leaves one. A meeting app that is still running will rewrite whatever you just removed.

The general rule this illustrates

Any app that has been through a major rewrite is worth checking for a second data folder: chat apps, note apps and design tools have all done this. The check is the same one line, sorted by size, run against the whole folder:

du -sh ~/Library/Application\ Support/* 2>/dev/null | sort -h | tail -20

Anything in that list whose app you cannot name is worth investigating, and that is a different problem again: the files left behind by apps you have already uninstalled. The same Electron shape shows up in Slack and Discord.