Illustrator CC 2017 won't open a second file
This seems to come and go, and has started on 2015 version. I can open a file fine, do what I need to do, but if I try to open a second file by double-clicking on the file icon in the explorer window (same way as done with the first one), Illustrator just freezes and I need to quit the software.
If I then try to open the same 'second' file, it works, but now it's the only one open.
The operating system does know what software to open as this has already being set.
If I try to open the second file via File > Open, it works most of the time.
I had to turn off GPU performance as that was slowing things down a lot.
Windows 10 Enterprise, 64 bit
Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz
32GB RAM
Any help would be great. Thanks.