"Your map differs from server's" - Easy Fix

A quick fix for this error that I've seen people getting.

Beforehand

There might be a few other reasons why it's not working.

1) You do not have enough storage space available
2) You currently have the wrong version of the map installed (delete the .bsp file and re-download it directly from the steam workshop. this may be a .gma file now).
3) The map installation location differs to your original gmod file location. (For example, your Gmod might be on your C:Drive, but your downloads are going to an external hard drive).

The Fix

How I fixed this Error for myself

Ensure your Garry's Mod is closed before doing any of this.

You can locate your Garry's Mod file by clicking on Garry's Mod (in your steam library) and pressing 'Properties'. Then click on 'Local Files' and 'Browse Local Files'. Then click on 'garrysmod'.

This is simple:
1. Locate the map that's giving you problems (this may be in the downloads folder of your Gmod files. Or the addons folder).
2. Move the file into the general 'garrysmod' file location. Note: Not 'GarrysMod'.
3. Select the map and place it into the 'maps' folder. It should be with next to other maps such as gm_flatgrass and gm_construct.

This should then fix your problem.

Hopefully it works as well for you as it did me.

[Spaceman [ꜥšꜣ]]

For me re-subscribing to the map on the workshop worked

[Darth Vader_techtips]

Great advice fixed in 5 mins

[Erteru]

This is not working

[Slenderman's Left Boob]

im using gm_construct and its still giving me the error, me and my friend both have the exact same addons, what do i do??

[MaxQ]

i put the addon that i downloaded in the maps folder. does that mean i fixed it?

[Altar]

tysm

[Korrosiv]

can also just delete the file and have server re download

[Nikushimi_]

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[kutasior z kutasiewic]

Worked for me Thanks a lot.

[francis]

didnt work, help plz