Microsoft Office Click-to-Run (SxS) using high CPU

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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

Best Answer

OK, a few possibilities: There may be corrupt cache entries. To clear the cache in Office 2019 / Office 365:

  1. Open the program "Office Upload Centre" with Run as Administrator
  2. Click Settings and Delete Cached Files
  3. Restart the computer

However the issue came back. Even doing a "Reset this PC" didn't help, when I reinstalled Office 365 with the default installer, the issue came back.

The finial fix for me was to install Office 365 32-bit (the default is now 64 bit), and the issue is fixed for now.

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