For the last several updates to Firefox I receive the following NSIS Error: ''Error writing temporary file. Make sure your temp folder is valid.'' Nearly every time the update completes successfully. My disk is 90% full and perhaps that is the problem although 20 GB remain. I have run disk cleanup to remove files, especially W10 Update files. Clear Disk Info doesn't identify any problem areas (all green). Any other likely sources of the message? Thoughts?