Reversing upgrade to Max 9
Pretty newbie question, but I have been avoiding upgrading to v9 because I have been working on a years long project in 8 and I’ve been concerned about things breaking in a (complicated) patcher. If I upgrade and that happens, is it easy to go back? I only ask now because there are a couple new features that would actually be super helpful in my endeavours. Sorry for a stupid question. I lurk the forum every day and you’re all an inspiration. Thanks!
Max 9 will duplicate your /Document/Max 8/ folders. - I think only the ones that you made - any packages that you down loaded have to be reinstalled.
Then you should open some simple custom stuff you talk about and see if it works.
/Document/Max 8 folder will still be there right next to 9. Nothing changed -
What breaks later is: if you change projects folder in max 9 they will not update in max 8 and visa versa.
So what I do is back up my entire project folder on an external drive and then drop it in to the newer version when or if I want to change version, which I currently do not do , but did before.
Makes sense?

Just grab the entire folder (in this case Max 9, in your case Max 8) and put it on an external drive - then when install 9 drop the Max 8 packages into 9 and overwrite everything. You cannot break it and if you do, you still always have your original Max file on your computer and on hradrive -
As far a working files go - those can put wherever y0u put them now. they will open in 9. if anything is broken - post here we fix it.
It is not clear if you use Mac or Win version, where things are a bit different.
On mac it is much easier, on windows max uses installers which can make your life a bit difficult.
In any case, backup your patches in first place.
If you are on Windows, safest thing to do is to NOT install Max but extract it's files from installer, leaving no trace of installation, which makes it easy to use many max versions on same PC.
Just post details,otherwise one can only guess.
And max 8 is not just simply max 8, there are significant differences between some versions.