If you have two (or more) different python installations on your computer edit the openage.bat in the install directory:
Replace the line python.exe -m openage with call "%INST_DIR%\python\python.exe" -m openage to start python.exe explicitly.
The newer versions of the HD Edition use another asset format. You need to have Patch level 4.3 to successfully convert the assets. You can change the patch level by doing this:
- Right-Click on Age of Empires 2: HD Edition in your games section
- Select "Properties"
- Select "Betas"
- The beta you want to opt into is "patch43 - Patch 4.3"
After you've selected the beta program, wait for Steam to download the files and try converting again.
Make sure you don't have UserPatch, compatibility patches or modifications installed that make changes to the original asset files.
If you have Wololo Kingdoms and various mods installed that change the base assets the converter will not work. A workaround would be to make a backup of your AGE2 directory and let the AGE2DIR environment variable point to that backup. In that backup at subfolder AGE2/resources delete all files except folders. Another workaround would be to backup your AGE2 folder and redownload it to have a clean install. After conversion you can replace it with the backup.
openage does not start a game by default on startup. Press the "generate game" button on the left or, if the game has not finished loading the assets, tick the checkbox marked with "create_when_ready".