Hi there!
I took out the HDD from an old Lenovo Thinkpad E531 (WINDOWS) and installed SOLUS on a different SSD without problems.
Having put back the original HDD to go back to WINDOWS (not my machine... 😀 ) I set the boot order back to WINDOWS BOOT MANAGER, then HDD, then DVD drive.
After restarting the laptop the WINDOWS installation on the HDD doesn't boot correctly, I can only get as far as black screen saying GRUB _ and nothing happening.
I searched for some trouble shooting routines but found only ones for getting back to a SOLUS installation.
Now, I need to get back into the WINDOWS installation.
Having taken out the HDD (WIN) before I started to install SOLUS on the SSD I'm sure that the SOLUS installation changed something on the BIOS level, I had indeed wondered why there was something called WINDOWS BOOT MANAGER. I had never come across anything like that before, and I installed SOLUS on a lot of laptops!

Any help?

Thanks in advance!
SOLUSfiddler

Lesson #1, have environment way you want it when installing. IE, don't take out the other HD.
Lesson #2, most problems are easily fixed. Suggest from Solus, you run/update the bootloader. In a terminal, run 'sudo clr-boot-manager update'. Reboot.

    dbarron
    Thanks for your reply.
    I had the environment the way I wanted it before installing SOLUS: I had a fresh SSD ready for installing SOLUS on. That worked without a glitch.
    I have installed SOLUS on a lot of empty, fresh SSDs on all kinds of Thinkpads, so I didn't expect anything to happen on the BIOS/UEFI level.
    And I need help with getting access to the (old) WINDOWS HDD, there is no SOLUS installation to operate from.

    Any new ideas?
    SOLUSfiddler

      I am 99.9% certain that nothing would have been changed in your BIOS. I'm not an expert in Windows, so can't help you with regard to EFI from Windows. Vague memories are something like correcting the bootrec, you might google it.

      I would give up on the dual boot, if that's what you got going.
      Take boot manager out of the bios lineup.
      Just commit to starting one OS at a time, meaning WIN the first boot or Solus the first boot.
      Separating the OS's has worked for me so my advice is purely anecdotal.

      **Hope I read everything correctly.

      I have SSD and HD. Installed Solus on SSD with Legacy (BIOS) and Windows with UEFI. In bions, i set the legacy for default and when i need to play games (windows), i just press F12 and select Windows (UEFI)

      This is strange. I've had a "similar" problem in a dual disk setup, where Windows installed the boot manager and its backup copy on the secondary disk. Legacy was on. I've solved deleting the boot mgr from the secondary disk and reinstalling Windows with only the system disk attached.

      You might be able to solve this with a Macrium Rescue CD. Download the free version of Macrium, make the rescue CD, and do the boot repair method.
      I'm not sure if this method applies to your situation, but every time I have used it, it worked.

      Hi guys!
      To get things clear: I used only one drive for WINDOWS (the original HDD) and one for SOLUS (my new SSD) respectively. Never mentioned a dual booting problem or anything similar, so I'm not sure if I've made myself clear enough in my original post or if the problem is that complicated.
      I ran either WINDOWS or SOLUS, never both on the same drive!
      Ah well...

      Problem solved for now:
      When I put back the original WINDOWS HDD to try and run WINDOWS again I checked the BIOS settings and selected "UEFI first" where I was given the choice between Legacy and UEFI boot. Then continued the booting process and everything was OK from then on.

      Ha ha ha:
      After all the hassle I convinced the owner of the WINDOWS laptop to stick with SOLUS. Worked (until further notice...)!

      Thanks for your trying to help!
      SOLUSfiddler