SMB3 level troubleshooting

Here is a list of some of the errors that can occur with SMB3 levels and guides to fixing them.

I've highlighted the errors that may only exist in Mario 3 Improvement in red.

This list was originally compiled by Spinzig and was last modified by hukka in 2005-04-23.

Symptoms Cause Solution
Game crashes There's a 'crash' object in your level. Remove or change the 3-byte 'Crash' object.
You have objects extending below 1B. Make sure objects end at 1A.
You made the 'END' object with the black background too near the actual end of your level. 'END' markers should be about 13 long, so if your level ends at EF, put the 'END' at around D2, at the very top of the screen, as it erases any ground below it.
Certain objects in your level will not work (3-byte ones). Plains levels: Remove the coloured block platforms that extend into the ground. Sea levels: Remove the grey platforms that extend into the ground. Underground levels: certain pre-made hills will not work properly.
Mario is starting on a wrong object (eg. a coloured platform with the screws at the corners). Put clouds or ground under the start place instead.
Too many enemies. The maximum amount of enemies on a level is 82. Remove some!
Level has been messed up by too many other levels being saved to the ROM. Re-save the file to the ROM.
A pipe has a door exit or vice versa. Pipes need an exit action of a pipe, and doors need the 'door' attribute.
Other, unknown reason. There are many other things that may crash the game, some of them unknown.
Weird looking blocks and background The graphics set for the level are wrong, eg. Ice with plains. Change the graphics to a compatible set.
Level plays fine, but black background is covered in white lines and looks messy Too many M3L files have been saved to your ROM. Unfortunately, the only way to stop it is to get a new ROM, so make sure you back it up, along with the original SMB3.
In the editor, objects are everywhere and there are things that aren't supposed to be there You put the 3-byte and 4-byte objects in the wrong order. At the very beginning of your level, create a huge stack of about 70 3 or 4 byte objects that you will take from and save the level. Reload it and check to see if the computer has randomly strewn rubbish through it. If not, put in the other half of objects (3 or 4 byte depending) and save under a different name. Again reload and check the level for mess. Once that's done, you can use the pile to drag objects and build a level without the error ever occurring.
Level starts with weird music or misplaced enemies Level has been messed up by other levels being saved to the ROM. Re-save the file to the ROM.
Mario goes into a pipe, but emerges in an underground level with no floor, and dies You used the wrong pipe object (A0-AF). Use pipe object 90-9F.
Ship or tank levels have weird blocks The graphics for a tank level must be set to 'tank', or ships to 'ship'. Some blocks like walls are incompatible with these. Change the blocks to something else, or change the graphics.
Doors lead to the next part okay but instead of leading where the pointer points, they come out in the same location as the one you went in (eg. door at BB leads to next part at BB) Certain checkboxes in SMB3 Discombobulator indicate how doors work, like the '?' box or 'off: entering pipe ends level'. The Lost Levels have this problem, so either design levels accordingly or turn off all '?' boxes. Make sure 'off: entering pipe ends level' box is ticked.
Some enemies and goal card missing near end of level Level has been messed up by other levels being saved to the ROM. Re-save the file to the ROM.
Enemies look weird/glitchy You placed incompatible enemies with each other. Space enemies out accordingly.
Enemies' colours look weird You ticked the 'weird coloured enemies' or 'bluish enemies' checkbox. (Not applicable to SMB3WS.) Un-check the boxes, or change the colours to your liking with the SMB3 Discombobulator.
Music is slow and weird Level extends into F0 and beyond. EF should be the limit of your level.
Glitched garbage at the end of a long level That garbage is all at F0-FF. You cannot put anything here. Change the length of your level to EF.
When you enter a door or pipe, glitched rubbish is everywhere, which disappears if scrolled off screen The pointer that door was connected to had, let's say 'C (vertical level)' in the vertical exit area. Only use this for vertically oriented levels. Change pointer to point to the regular number instead of the vertical one.
After an area with Bowser or Boom Boom and a door or pipe, Mario exits, but the level is misplaced and the screen won't scroll Boss enemies stop the screen scrolling when you meet them, this stays for the rest of the level even when you leave via a door or pipe. Remove or change the boss enemy to a normal enemy.
With the annoying auto-scroll removed, Mario enters the ship, but you can't see him, the screen scrolls by itself and the level is misplaced The 'Anchors Away' stage starts the scrolling, but the game gets confused as the ship no longer scrolls. Make the End Castle point to the ship instead of 'Anchors Away'.
After beating Boom-Boom in a sky level, the time rewinds and Mario dies Boom-Boom's crystal will not work properly in sky levels. Create a pipe leading to a plains or something and have the Boom-Boom fight in there, or give Mario infinite time.
Other enemies glitch at Boom-Boom They are either incompatible, or in front of him. Meeting Boom-Boom will change the palette tables when you meet him, however, have enemies in front of and behind him, and you will be able to fight all of them without problems, although the crystal ball will be glitched.
When Mario beats a Koopa Kid and gets the wand, the game crashes There is no End Castle in that world. To be able to get the wand and win, you must have an 'End Castle' level saved for that world.
Chain Chomps won't work properly and get stuck Chain Chomps have a habit of getting stuck to background and other things. Make sure that the level doesn't have a 'black background' object and that there are no bushes etc. around.
The enemies are compatible, but sometimes they glitch Many lifts and blocks with special actions (white throwing blocks) are not compatible with all enemies. Change the blocks or move the enemies.
Background etc. looks like garbage An object in your level sticks through the ground. Move it up out of the ground.
There are objects in the sky at the top of the screen that aren't visible in the editor Your ground or blocks extend down into 1B. They then stick through the top of the screen. Move the things to 1A.
Doors and pipes lead to the wrong places It's possible there is either another pointer around, or the original one was altered. Sometimes when you press 'Enter' on a pointer it will change it by itself, which is pretty annoying if you've just worked out where everything leads! Also note that due to the pointer implementation in SMB3, if you move a pointer at all, it will change its attributes.
Pipe levels have weird objects covering up some areas when they're made horizontally Uncertain. I'm guessing they need to be made vertical or just shorter.
Sideways Piranha Plants are invisible There is no 'black background' object, and in some levels the plants need it; otherwise they go behind the background. See below for putting in background.
Hilly or Underground levels have weird background, or the wrong sky colouring You need a background object. The only way to get background without it overlapping everything is to put it in as the very first 3-byte object in your level. This goes for every level that needs background objects to look right. Underground and Hilly levels need these too. (object 0E, Domain 0)
Objects in water or behind blank background etc. are erased when playing on the level, but are still there in the editor Objects were inserted before the water/background etc. object. Always remember that with background objects, you must put them in as the first thing in your level, before anything else. With water, either make the objects that are going to be in there (eg. Underwater hills, blocks etc.) after you insert the water, or put the water in before.
Mario enters vertical levels at the wrong place Uncertain. No solution as of yet!
All or nearly all enemies in vertical pipe levels are gone. Uncertain. No solution as of yet!