I realize this is an old thread, but I've run into this issue a few times when trying to take snapshot of our forums for development. Blank page, and unclear why. Can't rebuild master data.
When taking the backup, I exclude a lot of files from /data/ and /internal_data/ since they take up a lot of space and I don't need them on dev.
This file, however, is necessary:
/internal_data/install-lock.php
If you don't have that file, you can't rebuild master data, which you need to do to get the site back up. So, this is me documenting it, so next time I run into it, I can help future me.