OMG - I just discovered that I might have mistakenly blamed this incident on the web host.

After the "problem" has been "fixed" by the "web host", I decided to give the store duplication process another run, to verify that everything works smoothly and that I can perform that within less than 5 minutes.

I repeat the process and... the same problem occurs: fix_cache_key.php yields a blank page.

At this point I begin to understand that there may be something specific in my procedure that triggers this strange behavior... So I:
  1. Login to the admin console of the DUPLICATE store
  2. Take that DUPLICATE store out of DOWN_FOR_MAINTENANCE mode remember, the database was duplicated while the original store was in DOWN_FOR_MAINTENANCE, otherwise duplication could have unpredictable results).
  3. Run fix_cache_key.php


All works fine!

Conclusion: fix_cache_key.php should be run while logged in as admin and store is not DOWN_FOR_MAINTENANCE.

DrByte, is my observation/conclusion correct?