There are long running threads of Office Click-to-Run using excessive CPU (ie 30% or more) continuously, as per this post. The solution in that thread works perfectly for Office 2016, however the cache has been moved in Office 2019 and newer variants of Office 365.
Symptoms:
- Microsoft Click-to-Run (sxs) runs continuously at ~30%
- When Office programs have been open for a while, they also start running at ~30%
- Repairing or reinstalling Office has no effect
- Using the office uninstaller has no effect
- Manually removing all Office files from %LocalAppData% and %AppData% etc has no effect