ADDITIONAL SYSTEM INFORMATION :
It occurs in Windows 10, Windows 7, and I believe Windows 8 as well. It has occurred in very different environments including PCs with no special admin software beyond Windows Defender.

A DESCRIPTION OF THE PROBLEM :
I have not created a special regression for this, but it was never actually fixed for us. The problem description given by the previous user precisely matches what we and our customers experienced. I should add that the program uses SingleInstanceServer and only occurs when the program is invoked via its file association *via a web page download*. (I have experienced the problem in Chrome, but I have not verified it with other browsers. I can easily check if necessary) Once the cache has been emptied, the error always occurs until the JWS program is reinstalled. Update 8_191 did not fix the problem and actually just made the bug happen more predictably.

REGRESSION : Last worked in version 8u172

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
It's hard to provide a simple bug demo given that I *believe* SingleInstanceServer is a key part of the problem (I can verify this if necessary), and I *know* both file associations and using a browser to download the file that triggers the association are necessary to trigger the bug for us. I was surprised to find that the browser was relevant, since the application is not an applet, but it's still true. I can open the same files by clicking on them in the Windows Explorer, and then the application always works and does not clear the cache and uninstall the application.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Applying a file association should not remove the application from the file cache. Instead, the next time the application is opened, it should run as normal.
ACTUAL -
The error stack is the same as that shown in the previous copy of this bug (but in English instead of Spanish for most customers).

CUSTOMER SUBMITTED WORKAROUND :
We do not have a satisfactory work-around. The closest we have come is not to use file associations at all, and instead to use a process that monitors the browser download directory to see whether any new files have been downloaded and then automatically opens the application if files of the correct type have appeared. Disabling SingleInstanceServer is not a satisfactory solution for us due to the startup delays that SingleInstanceServer was designed to avoid.

FREQUENCY : often