Noticing that version 1.8.2 was now available, I attempted to install it. I only downloaded the file once, so it was not a download error.
The first time it did not give me any options for the location of the program (I use the default, C:\Program Files\Affinity\Photo), presumably as it was already installed.
The setup failed. That was all it said, no prompts about restarts or administrator rights.
I made a second attempt by running it with administrator rights. This time I had the prompt for the location of the program, I left it at the default. The setup failed again.
I then restarted the computer and ran the 1.8.2 setup file with administrator rights, and the install completed successfully.
I have attached the failure files here, having renamed the files slightly to add "fail 1" ... "fail 2" ... and "ok" in the filenames. Hope this helps with debugging.
For anyone else with the same fault, this is what you do:
Run the file "affinity-photo-1.8.2.exe" to install the application. It will fail.
restart your computer
right click on the downloaded file "affinity-photo-1.8.2.exe" and select "Run as administrator"
version 1.8.2 should now be installed correctly.
Hope this helps.
SetupUI fail 1.log
Setup fail 1.log
SetupUI fail 2.log
Setup fail 2.log
SetupUI OK.log
Setup OK.log