Possible to restore Time Machine to old macOS?

[Princess Cake]

Basically I'm fed up with High Sierra with what it's been doing to my iMac performance-wise and want to "downgrade" (to me it'd be an upgrade) to OS X Mavericks as its the earliest version my Mac supports. I'd like to know if I can restore a Time Machine backup made on High Sierra to Mavericks or if I'd have to just manually drag every file over that I want to keep?

 

[Intell]

You will have to manually backup and restore your files. You cannot restore a Time Machine backup to an older version of macOS

 

[Bart Kela]

Moreover, certain files are incompatible. I believe the Photos Library from High Sierra is incompatible with older versions (Sierra and earlier).

This may also be the case with the iTunes Library file as well but I'm not sure of the latter.

Anyhow, best of luck.

 

[Fishrrman]

As mentioned above, you'll have to do a "manual restoration".
It can be done, but takes some work.
If you want me to outline the process, I'll do it, but you must ask first.

 

[Princess Cake]

Quite alright, Fish. Little old simpleton me was able to figure out how to copy files from Application Support and various Document folders onto an external drive as temporary storage. Speaking to you now live from Mountain Lion where Apple is still sexy and Jony Ive keeps his mitts away from OS X.