Can I use symbolic links with PMDG products to free up my SSD?

I'm not sure it is recommended to do that. PMDG is not that big anyway you may have if you're on C a lot of things in "Documents\Prepar3dv4 Add-ons" that mayb ebetter to move as you just need to right click the documents folder to be able to relocate it anywhere via the Windows feature which is much more safe in my opinion.

Agree with Aurelien, you're not going to free up much space by using a symbolic link for \PMDG.  The major stuff is in simobjects and gauges.  Also, I'm not sure if the InstallWizard application is tested for use with directory join links.  For example, msi installers do not work.

I do use a symbolic link for Orbx.  This is recommended by Orbx, instructions in their forum, and this saves considerable space, 250GB currently in my system.

If the SSD you are trying to regain working space is your system drive, a great option is to create a separate Downloads folder(s) on a second drive.  I only keep system related downloads on the system drive, all my simulator, scenery and addons go on the data SSD and this saves me 80GB from being on the system drive.

Thanks for your comments I really appreciate your help.