-Part 1- Identify the Problem.
First, try opening the map in World Editor.
If you get a critical error go to Part 2
If you get "Unit Data Missing Or Invalid" go to Part 3
If you get Trigger Data Missing Or Invalid go to Part 4
If you get others (such as level data), post them here with the map.
After you solve your first protection problem, go back to this step. There will likely be more than one protection type used.
Open up the MPQ editor and open the map. Then do what the steps say to solve deprotection.
Part 2 - Solving critical error.
If you get a critical error, open up the map in MPQeditor, click on the map's name, right click somewhere not on a file, and click "Add File(s)". It should bring up a folder dialog. Find the folder "BaseMapUnits" and click "War3map.w3i" in there. It will ask if you want to replace the file. Click yes. Now there should be no more crit.
Part 3 - Solving Unit error.
If you get a Unit Data Missing Or Invalid, open up the map in MPQEditor. Click on the map's name in the list at the left, and click anywhere but not on a file. Click "Add File(s)" and go to the folder "Complex Files". Add the only one there (ill add more, like a blank war3map.j later). Click yes if it asks you to replace it, but its improbable there will be one. Should be fixed now.
Part 4 - Solving Trigger error.
This is the protection that most maps have. This is when you whip out Nathonmoxy's deprotector. First though, open the Mpq Editor and press "extract" on the war3map.j, the script file. Now open deprotector and press "Browse". Select map you want, select options you want, and press "start". If you get an error message like "obfuscation detected" you have no script in the map now. If you don't get the message "Map has been deprotected" tough luck, look at ch 5 for recreation of maps.
Chapter 5 - Recreating maps options.
If you want a map recreated in a new archive, you can post the map or follow the steps below.
1- Go to World Editor and save a blank map into the folder
2- Copy every MPQ file except the war3map.j (and the w3i if it causes errors)
You can use this one instead of using Nathonmoxy's deprotect.
Theres a small chance of it working, but when it works, it works pretty much perfectly.
Spoiler:
More tools - here
http://www.sendspace.com/file/xop8hm
NOTE: Password for the archive is "owner123", I just want to make sure people read this.