If modification is not running
Make sure that you are installed mod according to the instructions;
On Windows Vista, 7 and newer game must be started in Windows XP compatibility mode;
Disable (in Properties of shortcut or exe-file) Desktop composition and Visual themes;
If you see message about lacking of DLL-files, read ReadMe;
In some cases mod cannot be started because of problems with codecs (connected with startup logos that made as videofiles), try to rename or delete movies folder in game folder;
Can help reset of settings, for this you need to delete gta.set in saves folder.
Windows 10 compatibility
SweetFX library, that is used in the mod for some visuals, is not compatible with Windows 10, so the mod cannot be started. The solution now is to disable SweetFX.
Open enbseries.ini in the game folder and in the line EnableProxyLibrary=1 put 0 instead of 1.
You can change the graphics settings in the mod's menu, but each time when you change them, it's needed to disable the library again.
If even this didn't help: try to disable post-processing forcibly. For this move into another folder or delete file d3d9.dll in the game folder.
Martha's Mug Shot mission problem (was fixed after April 7, 2015)
Problem with Martha's Mug Shot mission, where you must to do shots with politician (black screen after cutscene) is connected with absence of correct camera files.
After April 7, 2015 mod was re-uploaded on Mod DB and this problem was fixed.
Diaz gang at Vercetti Estate in Freeride mode (was fixed after June 2, 2015)
Aspect, that it cannot be named as a bug, but it is not consistent to idea. As you remember, according to the storyline, Tommy takes away from Diaz his mansion (where Diaz gang is located, inimical to Tommy); after that this mansion became Vercetti Estate (where Tommy's gang is located). In Freeride mode instead of Tommy's gang in the mansion was still a Diaz gang.
After June 2 2015 mod was re-uploaded on Mod DB and this problem was fixed.
Note that released earlier patch Winter Mod (update — from 3.0 to 3.0 Updated) is not actual.
If you have problems with missions, you can install two copies of the game: with original game and with Winter Mod; try to pass mission in original game and then continue story in Winter Mod.
Bandicam (and possible other such programs) is conflict with graphics libraries in Winter Mod and them are not work (as result, some graphics features from the mod are not work). Run firstly Winter Mod and after this Bandicam (not in another order).
(Not problem of the mod too). If after mod's installation 3ds Max 9 (64 bit) not works, this is can be connected with DLL that was changed by DirectX installer; replace d3dx9_26.dll on this one from this archive.
Winter Mod 3.0 is incredibly stable modification and its confirmed by the record of complete game walkthrough (GTA: Vice City + Winter Mod 3.0). No one game crash or some other problems for a lot of days storyline walkthrough!
Thanks and have a nice game!