[chaley]

In my case the "restart" calibre command always fails if I am not running from source.

@kovid: I replaced main.py with logging. Using the code:

                x = subprocess.Popen([e] + args)
                prints('after Popen:', x, file=open('c:/users/charles/log.txt', 'a'))
                time.sleep(3)
                x.poll()
                prints('after poll:', x.returncode, file=open('c:/users/charles/log.txt', 'a'))

I get after poll: '0' in the log which means that the subprocess terminated. I got the same answer with and without the sleep(3).

It occurred to me that the startup might be fast enough where the restarted calibre is seeing the original one and refusing to start. One difference between Home and Pro might be the order that windows runs new processes. To test this I changed main.py as follows:
- first discard all previous changes then:

def main(args=sys.argv):
    time.sleep(1)
    if iswindows and 'CALIBRE_REPAIR_CORRUPTED_DB' in os.environ:
        windows_repair()
        return 0

where the sleep(1) was arbitrary. Restart now works.