According to a recent notice from RootsMagic.com, versions of RootsMagic older than 18.104.22.168 can no longer log into the FamilySearch.org Family Tree due to changes made by FamilySearch in their API. The API is the "Application Programming Interface" that is a set of routines, protocols, and tools for connecting third-party programs, such as RootsMagic, to websites such as FamilySearch.org.
The update to RootsMagic also addresses a Windows 10 problem that appeared in a last-minute change that didn't exist in earlier test versions of the program which prevents internal WebSearch from working, certain text from appearing on certain screens and breaks backing up to Dropbox and Google Drive.
It appears to me that Microsoft is waging a sort-of behind the scenes battle with providers of online storage other than its own One Drive. This is not the first time that Dropbox and Google Drive have stopped working on Windows versions. This also fixes random crashes by Mac OS X users.
If you have any of the older versions of RootsMagic, I suggest you go to the website and upgrade as soon as possible. Go here to see what is new. Click here to go to the RootsMagic Updates page.