We are trying to enable UEFI on systems that were upgraded from Windows 7 with Legacy boot and enabled BitLocker.
First step is to suspend bitlocker, then run mbr2gpt tool, then change BIOS settings to UEFI, Secure Boot. And after a reboot to resume bitlocker (and hide new D partition which is created when converting to gpt). But resuming BitLocker fails with an error that it can't access some file. Google tells that you need to delete C:\Windows\System32\Recovery\ReAgent.xml file. If we delete it, then BitLocker resumes. Although on restart it asks for Recovery key. So instead of deleting it we try to rename that file, resume BitLocker, delete newly created ReAgent.xml and then rename old file back to ReAgent.xml.
It works. But i wonder if we are not missing something. This file looks like a template of WinRE settings file, actually it looks weird with 0000 guides inside of it. Maybe we will have some problems later after doing such machinations?