instructions for the workaround for the less computer savvy.
right click on your gw2 desktop shortcut select "show file location"
Right click on the gw2.exe file (for me it says something like gw2_64.exe) select create shortcut. Keep the old shortcut as well.
Rename the new shortcut something so you know what it's for (I used Guild Wars 2 Workaround)
Right click on the new shortcut and select properties
In the target line add -usecoherent at the end, make sure there is a space between the end of what was already there and the new command (note if you're using steam you will need to add the command -provider Steam as well BEFORE -usecoherent with spaces inbetween)
click ok.
Use this new shortcut to start the game. When the problem has been fixed and the workaround is no longer needed you can delete the workaround shortcut and return to using the original shortcut.