Hi,

When will it crash?
1. After Click the Custom Background button (Before the Dialog shows)
2. After you selected a picture (Before the background actually changed)

If 1:
Maybe you have to grant the permission of this application and add it to your AV's whitelist.

If 2:
Does this happens to every picture?
If Yes:
...I need the log file for more details...
If No:
Some pictures are not supported due to format etc. Just use another picture or try convert your current picture's format / reduce it's size.

After 1. Sorry for the dumb question, but how do I grant permission to the application? And I have WE whitelisted.

Try find NekoWallpaper.exe and add it to whitelist. If it doesn't work, try launch it with admin privilege directly (rather than from WE) and see if you can change the background.
If all failed, send me (via email) the log file (only text files) from AppData (refer to FAQ\Other problem for the log location) and crash data (if exists, not required). I'll look into it but I can't promise it can be fixed since I can't reproduce this issue on my computers.

I readded to my whitelist, tried to launch directly with admin privileges, and they both did not work. I sent an email with the output log to you. Thank you for your help! And please do not worry if it cannot be solved! I can just stick to the default backgrounds! ♥

Hi, I have introduced a fix for this issue in today's update.

Ahhh it works!!! Thank you so much for your hard work! This makes me so happy! ♥