This article details how to run the scripts to reinstall the Configuration Manager client when it is either missing or non-functional.
Download the folder named "COPY LOCALLY" from Box to "C:\Temp"
Open "C:\Temp\Copy Locally", right click on ccm_reinstall.cmd and run it as Administrator
Press any key to continue, and wait for the CMTrace window to appear. Once you see it, wait until the log in the window reads "Returned error code 0" (This is uninstalling the client"
Close CMTrace and press any key to continue again
CMTrace will open again. Wait for the same exit code as above. (This is reinstalling the client and will take longer)
Close CMTrace and press any key to continue
Wait 5-10 minutes for the SCCM policy to update