Its very simple. The patch is deleting the file “11781_001001.ipf” itself.
Here is the solution:
Step 1
Go to Steam Library > Right Click on ToS > Properties > Local Files > Verify Integrity.
Step 2
When the verification ends, go to this folder (commonly) “C:\Program Files (x86)\Steam\SteamApps\common\TreeOfSavior\release” and look for “release.revision.txt” , open it and change the number to 11781.
Step 3
Now, go to “C:\Program Files (x86)\Steam\SteamApps\common\TreeOfSavior\patch”
You’ll see the file “11781_001001.ipf”. copy and paste it in any other folder. Then copy the new “11781_001001.ipf”.
Step 4 (last step)
-Time to play.-
Once you execute ToS, keep watching the “C:\Program Files (x86)\Steam\SteamApps\common\TreeOfSavior\patch” archives while the patching process. The “11781_001001.ipf” will vanish, paste the one that you copied right after the patch process reach 100%.
DONE. Go have some fun.