Now that i think about it, i think it was an activation issue. I had a dodgey made legal copy of windows 10 when they offered the free upgrade to even those with illegal copies of windows, but when i moved it, i needed to activate and didn’t know the key.
But two replies offering different bits of advice to my comment shows that at least in part its true that this is not straightforward
Were you using BitLocker? You need to disable that before moving the drive.
Now that i think about it, i think it was an activation issue. I had a dodgey made legal copy of windows 10 when they offered the free upgrade to even those with illegal copies of windows, but when i moved it, i needed to activate and didn’t know the key.
But two replies offering different bits of advice to my comment shows that at least in part its true that this is not straightforward