I decided to make this topic because of the occasional and annoying problems you can get when all of a sudden your mod makes no sense. The tiles are gibberish or the levels seem to have disappeared or Keen won't move. These are my findings and I would welcome those of others.
Back up your mod, preferably on a daily basis. (You can delete older backups.) I keep a sub-folder with my backups all labeled by date, keeping the last 7. It also helps to keep *these* backups on a USB stick to avoid computer failure.
CAUSES OF PROBLEMS:
PATCH FILE: Patch file may contain patches that interfere or are broken.
This is the most common cause of problems, especially with new or complex patches or long patchfiles. Patches can sometimes mess with each other or be incompatible, or they can have typos in them, or just not be patched right.
SYMPTOMS: Game crashes, error messages come up, something doesn't work the way it should.
SOLUTIONS:
* Run the game without the patchfile, see if the bug occurs. (Best with big bugs) If the bug persists, this is not your problem. If the bug vanishes then:
* Run the game with half the patches. (E.g put a %end halfway through your patchfile) If the bug vanishes, it's in the last half of your patchfile. If it remains, it's in the first half. Then you can repeat this step with the 'infected' half of your file and so on. Usually 3-4 halvings are all that's needed to find the bad patch. Or...
* If you have strong suspicions of what patch is the problem (E.g a new patch.) you can eliminate it and test.
If you find a bad patch see if fiddling with it can solve the bug, or ask another modder to see if they can solve the problem.
CONFIG FILE: The configuration file has been scrambled by a patch or game crash.
SYMPTOMS: Keen doesn't move/jump/pogo/shoot odd sounds, can't get past game menu. Game usually doesn't crash.
SOLUTIONS:
* Delete the config file and run the game. If the bug remains, this is not your problem.
* If the problem is solved, but comes back often, it is a patch problem fiddling with the file. If it comes back rarely, it is a computer problem, exit your game normally!
TILEINFO: Tileinfo file is corrupted.
SYMPTOMS: Tiles appear as nonsense, tile have gibberish on them. Tiles don't animate or animate strangely.
SOLUTIONS:
* I hope you have a backup tileinfo file. Usually this happens when the animation plane gets messed up. Remember never to create a new tileinfo file as most utilities can't create them from scratch.
PATCH PROGRAM: Your patch program has become damaged due to 'bit rot'
SYMPTOMS: Usually major, the game will crash or levels will be blank.
SOLUTIONS:
* Replace your patch program. This is usually a one-time problem. If it recurs, try copying your mod folder, deleting the original and then moving the folder back. (To get it off bad sectors in the hard drive.)
This can occur after a defragment, especially when not using the standard windows defrag tools. (If you find this, watch out for any movie files you have, they're even more susceptible.)