I made some minor changes to a regular map to play allied with a computer player against 2 other computer players. I set alliances and scripts for all players and shared vision for the ally. I want it similar to a melee game so all players have custom scripts and the same units as a melee game. But the ally player (terran expansion custom AI) only builds 1 supply depot and 1 barracks, and nothing else, no more units and only scv's keep gathering minerals. The other computer players work ok (both zerg expansion custom AI). I made very little changes so what could be wrong?

The player's race.
No location over the start location/main building and/or not running ai at location.

all of those are set up correctly.

Randomized Start Locations has to be disabled or the computers might get a slot with the wrong race.

That was also set up correctly. Everything is set up similar to the other two computer players (zerg) that do work ok, only difference is that this is a terran player (expansion terran custom AI) and allied to a human player.

post the map

Make sure you arent using a campaign A.I
And for that matter, make sure the correct A.I is being used. Like a protoss a.i for protoss and a terran a.i for terran etc.

yes i already checked for correct AI.
here s the map:

Attachments:

Has anyone checked the map?

One thing I forgot to mention, another change I made to the map, different from original, is that I changed player 2 and player 4 location (but location is moved to the right player). But I don't think this makes much of a difference.

I have checked the map but couldn't find the source of the problem. However melee simulation is not exactly my specialty so I might have overlooked something.

I can only recommend try remaking the map. But this time take small steps.
No terrain and 2 players at first then test. Add stuff and test as you go. Maybe you find the factor that makes the Terran player inactive.

I noticed something strange. I made the map again but this time I did not change the player 2 and player 4 locations. And now the terran AI works ok! How could this be?

It was most probably some random bug by ScmDraft not yet discovered and had nothing to do with changing locations.

I thought it might be an error with the terran custom AI. For some reason, the player doesn't find the gas next to the base. If the base is placed elsewhere, again, the gas next to the base is not found, but gas is gathered from a geyser far away. I tried insane AI, and then the gas isn't found either.

okeee this is a problem that i have encountered when making a ums out of allied fortress. It happens because the minerals/geysers are placed awkwardly. The only thing u can do is placing the minerals at different locations and see if it helps

I'll try replacing them, but what exactly is so awkward about the placement, i don't see much difference with other regular maps.