In new Ubuntu OS, the default Desktop session is Wayland. there is a possibility that you will encounter the issue that the captured screen image is a black screen. 

Here are the solutions to deal with such issue. 

Solution 1:

1. Launch Worksnaps Client using command line. You can open a Terminal, then execute commands:

cd ~/WSClient/


If your machine not installed gnome-screenshot command, you can install it with: sudo apt install gnome-screenshot.

This will start Worksnaps Client. You can log in using your account, select project/task, and start to log time. Please check whether screenshots can be captured normally. 

2. If screenshots can be captured normally by using command line, the next time you can use the desktop shortcut to start Worksnaps Client (i.e., using the usual way), then the screenshots should be captured normally as well.

Solution 2:

1. Create a text file <home>/timetracker/display_type.txt. (You can use vi or your favorite text editor.). You should already have a folder named "timetracker" in your home directory, you just need to create the file display_type.txt under the "timetracker" directory. 

2. Put a single line into the display_type.txt file. The single line will be "wayland" (without the quotes). Save the file display_type.txt. 

3. Start Worksnaps Client as usual. 

4. When screenshot is captured and uploaded to the server, check to see whether correct screenshot can be captured.