Question regarding the Data file.

[HalfJaw]

If I delete the contents of my data file and replace them with a backup, will the mods contained within be treated as newly installed once I load the game? For example, will certain settings revert to default or will I, say, need to re-find keys to player homes? I installed an update to a mod that didn't quite work and I'm hoping to return to the version I had installed before, but I'm not going to bother if restoring backed up files resets every other mod.

[Miku]

if you replace mod configs you will ahev them usually reseted to default.
otherwise, not. in my experience, others may vary

[We Are Groot]

If you delete your data files and replace them with an earlier backup it won't really treat them as newly installed mods as long as all the data files you are replacing have the same name. For example you won't get the message that this save relies on content that no longer exists or whatever if you replace The.esp with an older version of The.esp because it is the same mod.

With a lot of mods copying over an older version might not cause any real problems. If there are drastic changes between versions then you could run into some trouble. It depends on the mod and exactly what it is changing.

I have made changes to mods and sometimes I didn't like changes that were made so reverted back to an earlier version but because I knew what was changed I knew it wouldn't give me any issues.

The best bet is to have an earlier save.

Oh and you won't need to refind keys for players homes because that is stored in your savegame not in the mod. Unless of course you are replacing a mod that changes keys to houses with an older version where those keys no longer exist.

[Stoob]

You might need to re-look at the list of mods in the Skyrim launcher (or NMM or whatever u use) to see what mods are checked/unchecked as the *.esp's may have changed to different versions which may not necessarily be picked up automatically and treated as new.

[countryraven]

just swapped out mine for a backup data file
to "solve" a weird problem
and "IT WORKED" like a charm

i deleted everything in my trash can first
so if i need to retrieve anything from the "old" data file
it will be quite easy to do

[HalfJaw]

Thanks for the info. Good to know that I can safely fall back to both a backup and its corresponding earlier save.