That’s one way to solve it. An easier way would have been to open it in SketchUp 2016 and used File>Save as… Set the file type to SketchUp 2015. With picture:
thanks I’ll work on that. You guys.are soooo smart 
Regarding the original issue, I contacted pro support, and they said it is
a known issue that will be addressed in the next update. Still trying to
figure out what to do in the mean time, though. They haven’t gotten back to
me on that.
And whether or not the fix works for you, please post again here to let the community know!
YES!!! The maintenance release worked. Thanks to all who replied!
To restart explorer in task Manager. And the strings will be shorter.
Great fix! Everything works very well! Thanks!
I have the same problem can you tell me if you’ve resolved I can not open the file in SketchUp, if I try to open it, the program immediately Becomes unresponsive and Appears to note in the status bar at the bottom of the screen saying " this is a very long string. How long do we want? " and then never opens.