Xanadu

Further to my above post, I've found it more effective to delete the new BPT version by double-clicking uninstall.exe. I've also found that Windows 10 can still be downloaded from "https://www.microsoft.com/en-us/software-download/windows10". If the Media Creation Tool fails, it is usually because TLS 1.2 needs to be properly installed - Google for details. I haven't tried installing it yet, but apparently you can install it without a product code. The result isn't pretty, but it should be fine for running BPT, which is all I ever do within a 64bit system.

I've had the same experience, although fortuitously our submission has already been submitted under the previous BPT version. The fact that the latest version fails to save a rollback copy of the previous installation must count as a programming error. My suggestion to the OP is to delete everything under "C:\Program Files \HMRC" and reinstall previous version payetools-rti-24.1.24086.542-win. The database file sqlite3.db will remain unaltered in "C:\Users\Public\HMRC\payetools-rti" together with any database backups. That should do for this year, but we all have the problem going forwards as Windows 10 is no longer straightforward to source, install and activate on an existing system, and everything I've heard about Windows 11 as a business operating system is negative.