Here's what I do.......
I make a directory and name it APCD - Back Up - 1
I copy paste my "good" APCD directory ( everything in it ) into that directory.
Then I have a "back up" of the good directory.
When something messes up, let's say my textures get messed up, I only have to copy paste the backed up files ( not the other directories ) in my back up directory to my current working directory.
If I have my objects vanish into thin air or they get messed up, I back up my course directory and copy paste the "entire" backed up APCD - Back Up - 1 files ( including the directories ) and overwrite everything. Then copy my backed up course into the now fixed APCD course folder.
I am then good to go till the next APCD snafu.......
Hope I explained that well enough......it always works as long as I have a backed up APCD directory.
Every time I do major object work, I always re-back up the good APCD directory and name it APCD - Back Up - 1, APCD - Back Up - 2 and so on......then I have history.
Sage.....

If there is one thing ................ummmmmmmm.......I can't remember.