According to the screenshot, the problem is what I originally mentioned:

According to your Firefox icon which is cut off a bit, my guess is that you're using the no_width_limit advanced option, and you made your taskbar too narrow. Unlock it and enlarge it just a little bit, so that the icons are not cut off. Let me know if that fixes the problem.

And regarding:

It happens whether or not no_width_limit is enabled.

It's not enough to just disable no_width_limit, because the taskbar might still stay narrow. You need to make sure the option has no effect by making the taskbar wide or by restarting explorer.

OK, that's a start. Do the icons only disappear when the no_width_limit option is enabled? Can you post a fresh screenshot of your taskbar?

See my last reply which is still relevant. I created test builds specifically for you. I can't help without your cooperation and without being able to reproduce the problem.

Yes, try it, it wouldn't hurt. From the code it seems like error 5 is supposed to happen only in case of a crash.

Other things to try:

• If you have other customization programs, turn them off to check whether there's a conflict.
• Try turning off all options (if they are disabled, you can temporarily use a portable version which will have all options turned off). If there's no error in this case, try to enable the options and find which option causes the error.

I assume that explorer crashes when the tweaker launches, right? Can you create and upload a crash dump using ProcDump? Run procdump64.exe -mp -e explorer.exe and trigger the crash. The dump will be written to a file, the details will be printed in the ProcDump console window.

There should be an error code after "could not load library", which code are you getting?

Please make sure that you're using the latest version of the tweaker, v5.12.3. If not, I'll try to understand what's going on by gathering more information.

Fixed in v5.12.3.

Thank you for the suggestion. Closing as a duplicate in favor of:

https://tweaker.userecho.com/topics/1175-option-to-remove-the-show-hidden-icons-arrow-from-the-system-tray

Please try the newly released beta version, v5.12.2.1.

That's tricky - depending on the program, running an instance of the program which was managing the closed window might not be enough. For example, most browsers have a "reopen closed window" option, but without being familiar with the specific browser, the tweaker won't know how to restore that closed window. Another example is Notepad - how would the tweaker know which document was open in the Notepad window which was just closed?