Which GPU is in your computer? We're looking to get this fixed soon, and knowing which OS and GPU combo people are using will help us out a lot.
Here's instructions on how to work around the problem:
1. Switch to previous_alpha. Steam library -> right click Overgrowth -> Properties -> Betas tab -> click on "NONE" and switch it to "previous_alpha". Hit OK.
2. A download should start. It will show "downloading" at the bottom of your screen. You can click on that, and it will show you download progress. The download should be about 240mb. Wait for this download to complete.
3. Clear the game's write cache. Instructions are here:
http://wiki.wolfire.com/index.php/How_t ... me's_cache
4. If you have a Windows machine, then install this MANUAL patch file:
http://cdn.wolfire.com/techsupport/over ... ns-win.zip
To install that manual patch file, extract the files, and overwrite the files in your Overgrowth install folder. By default, this is in C:\Program Files (x86)\Steam\steamapps\common\Overgrowth - make sure you unzip all the files in there, not in a sub-folder, and overwrite the existing files
(If you have a Mac, you should not require this manual patch. Switching to previous_alpha should fix this error message for you).
Now you should be able to run the game, and it should say version 1.0.6. Check in the game's main menu -> top bar -> help -> about.
If you have additional problems after this, please make sure you are clear about the exact error message you are getting. The shader error should no longer appear if you've followed all these steps. It is possible that some of you might still have other problems, but those are going to be related to different bugs, and will have different steps to fix them.