Troubleshooting - drawpile/Drawpile GitHub Wiki
Missing MSVCR70.dll error
Make sure you have the latest OpenSSL library version installed. A Windows version is can be downloaded here: http://slproweb.com/products/Win32OpenSSL.html
Ffmpeg executable not found
This message is shown in the video export dialog if Ffmpeg is not found. Ffmpeg can be downloaded at ffmpeg.org. Set the path to the ffmpeg executable in Drawpile's preferences dialog.
Wonky/unusable lines when using a graphics tablet
This problem is most likely caused by an incompatibility between Qt and the graphics tablet driver. As a workaround, try disabling tablet support from the preferences dialog. This causes Drawpile to treat the tablet like a mouse, meaning invalid data in the tablet events get ignored. A downside is that you will also lose support for stylus pressure sensitivity.
Since Drawpile 0.9.9, there is an option to enable a tablet event bug workaround mode. Try this before disabling tablet support entirely.
No pressure sensitivity with Surface Pro 3 pen
You need to install N-Trig's wintab drivers.
OSX: "Drawpile" can't be opened because it is from an unidentified developer
Since I am not a registered Apple developer, the Drawpile package is not signed. To run it, go to Security and Privacy section in System preferences. There should be a label '"Drawpile" was blocked from opening because it is not from an identified developer' and a Open anyway button. Click on the button to allow Drawpile to run. You only need to do this once until you upgrade Drawpile again.