This is a known problem since as early as June 2015 without a solution to date (08/20/15).
From personal experience, all the files in the <user>\Documents folder are being set to ReadOnly. Since RootsMagic seems to default to the users documents folder for its RMGC files (this is not accusatory, simply a statement), this means that an attempt to open the file results in "Error: unable to open database file (8)" or "... file (14)"
I've tried to change the RO attribute thorugh file properties. It says that it's done, but the file remains RO.
I've also through both Cmd.exe and SuperShell to "attr -r -a -s -h *.* /s" on the documemts folder, after performing the operation, the file (and folder?) remain RO.
Taking ownership of the file, either directly or with MS's TakeOwnership add on to the menu provided me with access once at which time it returned to being RO.
Renee (tech support here) pointed me toward, among other things, http://superuser.com...der-windows-8-1 which - at the moment - seems to work. Note that some of the text is different between v10 and v8.1 but the steps are the same.
I'll follow up if I find any more information on this. And thanks Renee
Edited by AlJones, 20 August 2015 - 12:23 PM.