A Steam Community announcement announces Spintires has returned to Steam after recently being pulled from sale due to problems that some speculated were deliberate sabotage due to an internal developer/publisher squabble. Here's word:

First we apologize again for the recent issue causing crashing of spintires and the delay in resolving this.

We are pleased to say we have now released a fix for the recent crash onto Steam.

In the next few days we will release a full and frank statement regarding the cause of the problem and how we plan to avoid this happening again, as well as details of the next update we have been working on since the start of 2016 which we plan to start testing next week.

For now follow the instructions below and start to play Spintires again!

• If Steam is running, exit Steam before follwing these steps.
• If you applied the dll fix made by forum user Localhost that was on the forum, please remove it first.
• Start Steam and it should automatically download the update.
• Now start the game, it should display 03-03-2016 in the bottom left corner.

If you have mods or custom changes and face any problems after trying the above please follow the steps below:

• Shut down Steam
• Go to Steam folder and then to steamapps\common\Spintires\Media and temporary move ALL your mods to other directory (also delete any dump files you might find)
  By default it is: C:\Program Files (x86)\Steam\steamapps\common\Spintires\
• Press combination Logo Windows + R, enter %appdata%\Spintires and click OK
• Delete all subfolders and files except UserSaves (this will reset your config)
• Run Steam
• If the game was already updated please verify local game files, otherwise wait until automatic update is applied
• Run the game
• Re-add your mods

If after following these steps you get a message "game files differ, multiplayer and achievements", then please follow this guide.