Installation of LTSpiceXVII March 2021 version on Windows 10 machine gets "disk full or permission problem"

I have Admin privilege and am running LTSpiceXVII.exe as administrator on a PC with over 50 GB disk free space.

Started with fresh download of LTSpice -- today 4/5/2021.

Installer runs for a minute then throws popup

"Trouble writing: C:\Program Files\LTC\LTspiceXVII\LTspiceHelp.chm

Trouble uncompressing file: "C:\Program Files\LTC\LTspiceXVII\LTspiceHelp.chm"

Disk full? Permission problem?

This might be curable with fresh reboot."

Clicking "ok" abandons the install

I tried rebooting, and installation still fails.  I tried LTSpiceXVII downloaded about a year ago, with the same failure.

Fred Belsak

Fixed spelling typo
[edited by: FBelsak_at_AMAT at 2:20 PM (GMT -4) on 5 Apr 2021]