To recreate the bug:XNViewMP: xnviewmp.exe -System Error
This program can't start because zlib1.dll is missing form your computer. Try reinstalling the program to fix this problem.
1) Download XnView MP 0.78 Windows ZIP version.
2) Extract file and create an empty xnview.ini file (just to be sure it's not loading settings from somewhere else).
3) Run xnviewmp.exe and go to Tools -> Settings... -> General -> General tab -> under Startup uncheck the "Open browser" box.
4) Close and restart XnView MP
5) Go to Help -> About and you should get the above error message.
If you go back into the settings and recheck the "Open browser" box, restart and go to Help -> About again the error message will no longer appear. It therefore seems this issue only occurs when you have XnView MP starting in view mode and doesn't occur when you have it start in browser mode. This bug didn't occur in 0.72, but it does occur in 0.78 and I'm pretty sure it was in 0.76.
It's very minor, but I thought I may as well report it.
Thanks for the great work on XnView MP.