Launcher will not recognize downloaded engine

Just got UE4, love how everything looks. On a metered net connection here, and need the editor on this desktop. Went and downloaded it on a laptop elsewhere, and copied the whole install folder back to my desktop. Should work, right? Apparently not. Go to open the launcher, and it starts downloading the engine again. Does not recognize the engine, or the content downloaded. Is there a path I need to change in an .ini file?

Also of note, on my desktop, put UE4 on my E: drive, whereas on the laptop it was in the C: drive.

I believe there are known issues with installing to any location other than the C: drive.

Is there any workaround? I can open the editor, and it works fine, but it starts the launcher and tries to download the engine again. Then I just close the launcher, and go back to the editor, and it all works until I open the editor next time.

You need to follow this guide:

Tried a fresh install on the C: drive, copied over the data from the other comp, still won’t recognize it. Any help?

Thank you ever so much! It works!