The most recent Calibre Portable wouldn't launch. If I reinstalled, it opened, may open once more, but most I'd get out of it is 2 launches then nothing happened.
As per other's troubleshooting and advice:
- I tried opening in safe mode
- It wasn't opening off screen
- I deleted Calibre2 folder under program files
What worked was turning off Windows defender and adding an exception for the .exe file
As per guidance here:
https://manual.calibre-ebook.com/faq...ing-on-windows