AppData is being written to the wrong place

I recently had my Windows 7 desktop PC upgraded to Windows 10 by a local computer shop. I had them do it because they had built the machine and were familiar with the hardware. They recommended doing a clean install of Windows 10, so when I got the machine back it was necessary to re-install all my programs.

Here is the most important detail: On this machine, the OS is on C: (a 512 GB SSD) and my user profile is on D: (a 4TB HDD).

Here's the problem: programs are writing their application data to C:\Users\John\AppData rather than D:\Users\John\AppData. I know this because all the AppData on D: is dated before the upgrade, and all the AppData on C: has been created since the upgrade. I should have noticed the problem when I found it necessary to reset preferences in programs like Lightroom and Photoshop. These programs should have used the existing preferences!

I assume some environment variable was either not set, or was not set properly, by the technician who did the upgrade. If so, I'm hoping that the fix is as easy as (1) setting the variable properly, and then (2) moving C:\Users\John\AppData to D:\Users\John.

I'm not confident enough to attempt to fix this myself. I'll take the PC back to the shop and have them do it. But I'm hoping for some assurance from the community that the fix will be simple.

Just to be clear: My user profile is D:\Users\John. It has all my data (Documents, Pictures, etc.). So it does not need to be moved.

However the system also created a profile C:\Users\JOHN\, and it is writing AppData there, rather than to D:\Users\John.

For your information, here is the contents of C:\Users\John\


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The point of having a fast ssd is to load everything fast so why put a lot of often used data on drive d which is slower. With 512 gig of space you sould have plenty of room on the ssd.

If you open a cmd prompt then type

Set

what does that setting say about appdata

I have more than 2 TB of data on my D drive. The C (system) drive is only 512 GB.

APPDATA=C:\Users\JOHN\AppData\Roaming

The site blocked me when I tried to include the entire output of Set

It uses that variable to save the data to. Things in appdata are used all the time so should be on ssd for speed My c drive has only 88gig used thats with all my software data is fine on a spinner

Are you saying that I can live with AppData being written to C while all my other user data (desktop, documents, etc.) is on D? Is it a common thing to do? It seems to me that most of the time users rarely if ever need to poke around in AppData. That's why I didn't notice the problem for over a month. But I have one program that is used to make measurements, and that program exports those measurements to directory under AppData (a poor design, in my opinion). Under Windows 7, I was used to finding the export directory under AppData on D. It's when I went to look for measurements that I discovered they were now being written to an export directory under AppData on C. If it weren't for that program, I might never have discovered it.