Tobi freezes after Windows sleep


Hi all,

Tobi freezes when the computer has been asleep. Problem is on Windows 7 and 10.
Sometimes I'm able to quit the program, other times I need the taskmanager to force quit.
Somebody familiar with this problem?


The same behaviour appears when the PC is locked (Windows-button+L). Immediately TOBI is not working anymore. Can this be solved ?

I am able to reproduce this behaviour on Windows 10 with Tobi .NET4 (not .NET3). I think this is a known bug with WPF (the UI toolkit used by Tobi). I am looking into it now...

The current workaround is to open Tobi's preferences dialog, search for the "WpfSoftwareRender" option, and set to true by checking the tick box. Please let us know if this works for you. Regards, Daniel


I've tested your workaround. Unfortunately it doesn't work...


hello, did you restart Tobi? daniel

I thought I did, but appearently I did not.
It works after a restart!

I looked into this issue further, and I implemented a fix / workaround (will be available in next release). The current recommended workaround consists in setting WpfSoftwareRender in Tobi's application preferences, but this obviously disables hardware-accelerated GPU rendering, and consequently creates more CPU load during typical heavy audio waveform layout. So, I researched the root cause of the problem and I narrowed it down to a WPF bug (WPF is Microsoft's user interface toolkit used by Tobi), which is reproducible easily when invoking CTRL-ALT-DEL followed by cancel, or during a UAC prompt (User Account Control), and of course when screensaver lock out+in. The bug is related to the use of BitmapCache which is a performance optimization for .NET4 (thus why the bug doesn't occur in .NET3 builds of Tobi). The UI redraw freezes, but the UI is actually still reactive to keyboard and mouse input. In fact, a resize-down of the bottom waveform area makes the window responsive again. This is not just the main window, the bug also affects the popup window for image descriptions (which has its own audio waveform recorder component). Apparently, there is a more "brute-force" heavyweight solution which consists in manually killing dwm.exe, or programmatically via DwmEnableComposition(0) ... but this would result in the entire screen flickering, it would not just affect the Tobi windows. So I am not keen on it. The bugfix / workaround is now in the source code: (will be released soon as part of Tobi's maintenance cycle) Regards, Daniel

This issue is solved in Tobi v2.6.1.2