I can't download pc gamepass games to my external ssd D Drive.

I see, just to test. The download starts just fine if select C: drive, right?

Oh, sincerely the best option will be backup the files.
There is a workaround to do the conversion but can corrupt files in the process

We can try create another partition, then designate that new partition as where new apps are going to be installed and finally try on the Xbox App to see if now you're able to select the new drive.
(Don't forget to create the new partition as NTFS?

In case that you was able to select that new partition, the best option would be format the desired one as NTFS and assign that drive to install new apps by default again

Thanks im doing fine, and yes i have changed where apps download by default. It still tries to download to C

If that doesn't work you could try to do the following

Open Settings, click Update and Security and then Windows Update;

Click Check for Updates;

Click the Download and Install Now option, if available;

Also, check the Microsoft Store for any updates on the Xbox apps and its services.

if everything is up to date do this:

Go to windows settings > apps > search for gaming services app > click on it and select advanced options.

After that, click repair and then restore, open the app and try again.

Then do the same for the Xbox app:

Go to windows settings > apps > search for Xbox app > click on it and select advanced options.

After that, click repair and then restore, open the app and try again.