How is this possible? 

Solidworks can't even open a file?

SW '15 patched to SP4 and it crashes when you try to open a file.  or save a new file.  or save as.

Windows 10.

Works in all previous releases, but with SP4 it dies.

I am really sick to death of Solidworks buggy software.  Releasing products that have major BUGS is totally unacceptable!

\$5000 a year and I had to spend my whole day diagnosing this serious BUG.

Please start debugging your software before releasing it to the public and charging them thousands of dollars a year.  Not to mention the original purchase price.