How do I fix this DarkRP Error?

[Great Dog]

Every time a user joins my server, it always spams this in console:

[DarkRP] gamemodes/darkrp/gamemode/modules/base/sh_gamemode_functions.lua:5: attempt to index field 'Sandbox' (a nil value)
1. unknown - gamemodes/darkrp/gamemode/modules/base/sh_gamemode_functions.lua:5

How do I fix this?

[McDunkinY]

Did you remove the sandbox gamemode?

[Great Dog]

no.

[Aarone2004]

Did you rename the sandbox gamemode?

[Great Dog]

[QUOTE=Aarone2004;50703177]Did you rename the sandbox gamemode?[/QUOTE]

nope. Though, I do remember opening a lua file in the sandbox file on accident but I didn't edit anything.

[Aarone2004]

I'm not an expert, but maybe you can go to GMOD's github and try re-downloading sandbox and placing (replace all files) it on the gamemodes folder.

[blueangel512]

sandbox should be low case and not Sandbox, I think, try that.