Question Can't boot to new SSD unless old HDD is connected

Sep 20, 2020
Hello everyone, recently I installed an SSD and installed windows 10 to it to act as my main drive, I still kept my old hard drive with a windows install + all my data (mostly games) since it is a 1 tb drive while I only have a 500gb SSD.
When I try to boot from the SSD (from bios>boot menu) I get thrown back to the bios after a few seconds of black screen, however when I boot from the old drive I get a menu asking which windows install I want to run, if I click the new one I can use it normally, and I've been doing that, however if the old drive gets damaged I lose access to the SSD.

One thing that called my attention was that the HDD in the boot menu says "Windows Boot Manager", whereas the SSD only says the model name and size.

If any of you guys has any idea how can I fix this (preferably without deleting all my files) I would be very thankful.

PC Tailor

When you clean installed Windows, did you disconnect the old HDD? Problem with windows installation is it can install boot partition/data on the secondary drive and therefore makes the OS unusable without both drives installed.

Thus why it is guidance / best practice to disconnect all other drives during the installation process:
When you install windows, it will try to put a hidden recovery partition on a second drive if one is attached.
I think this is your situation.
You will not be able to boot without the recovery partition.
If there is only one drive present at install, the recovery partition will be placed on the boot drive.

Remove all drives and reinstall windows on your ssd.
Later, you can attach the old HDD and do what you wish with it.