Can i install 2 versions of windows with each sharing the same user data files

Question

I wanted to figure out a way so that I could install 2 versions of Windows 10 on the same hard drive. I know I can do it by creating multiple partitions but the catch here is that I want both versions of Windows to access the same user accounts and the same user data files for each of them; and if further possible they must even be able to share the installed applications (I know after upgrade that my apps work just as fine on both versions)

P.S I know that installing Windows and another OS like remixOS on the same disk partition works very well but installing 2 versions of the same Windows can cause problems which solution is exactly what I am looking for.

Answer 1

No, here's why.

Parts of the registry live in different places. c:\windows\system32\config

However, each install will need to have separate unique copies of the the registry.

Also in the users folder is the NTUSER.DAT file which is another set of registry entries.

So you will install an app in c:\windows and c:\windows10-2 and core registry files will be different. Any program installer is used it will install registry entries in the current OS, and the other one.

Also due to unique user SIDs it will cause further problems.

I don't know if windows will even allow you to symlink core registry files. My documents, and the other subfolder will symlink/junction easily.

Also NTFS file permission could add an additional layer of complexity to the situation.

You might succeed in junctioning the files, but the end result will be nigtmare to keep in sync.

Answer 2

Maybe if you have a domain and both installations are part of the same domain and you use a domain account. Your biggest issue is dealing with the account SIDs which the file and folder security is tied to.

https://technet.microsoft.com/en-us/library/cc778824(v=ws.10).aspx

The SID is unique to a username / PC or domain combination. Local accounts, even if they have the same SAM name, will have 2 different SIDs so they won't have the same permissions to the folders/files. As far as Windows is concerned, they are two totally different accounts. You can give each of the two different accounts permissions to the other's files, but that would be a real pain. Not to mention, you can't do anything about the different registry hives and things linked to those.

I am curious as to why you would want to have two different versions installed to begin with. There might be a better way to do whatever you are trying to accomplish.