Hi @FDionne,
I spent over an hour on the phone with support and did not get anywhere. Did some searching online and came across another thread experiencing the same issues and the solution there worked for me. Here's the thread: https://ttlc.intuit.com/community/taxes/discussion/turbo-tax-deluxe-2021-won-t-install/00/2389040.
In short, I changed my environmental variables for TEMP and TMP to C:\Temp and then I was able to install properly. If you want to give it a shot, here are the instructions I followed. Good luck!
"Type "environment" in the search bar, which should bring up "Edit the System Environment Variables" as a match. Clicking on it takes you to the "Advanced" tab of a dialog box titled "System Properties." Near the bottom of the dialog box, click on the pushbutton labeled "Environment Variables...". This brings up a separate dialog box that shows the current values for user environment variables at the top and system variables at the bottom. In the list of user environment variables, you should see both TEMP and TMP, and their current values. Click on each, then click on the "Edit..." pushbutton. This brings up another dialog box in which you can change the "Variable value" to "C:\Temp" (be sure to change the variable value, not the variable name). This folder must, of course, exist for this step to work properly. OK out of all the dialog boxes and retry the install. Environment variable changes take effect immediately, so if this is the only change you make, it's not necessary to reboot."
