Unknown class FirstViewController in Interface Builder file

Question

When I run my application i got this I see in my console this message \"Unknown class FirstViewController in Interface Builder file.\"

I am running TabBar applicati

Answer 1

When you add multi project to Workspace. If you use the same Product Name in your's projects. It can conflict.

Rename Product Name in the projects have a same name.

... Hope this help ....

Answer 2

Right click on Storyboard --> Open As --> Source Code

Find your unknown class name in the storyboard source file. It may be because you have accidentally assigned a custom class name for one of your UIView subclass'.

Answer 3

Go to project , targets , build phases , compile Sources and add the unknown class ..done.

Answer 4

This can also happen if you use the same package name for multiple projects (if you're being lazy with your provisioning). Go into your user directory, then go to Library/Application Support/iPhone Simulator/[your sdk version]/Applications and delete what's in there. You may also have to delete the app from the device. That will remove any accidental references to files from other projects, which can cause this error.

Answer 5

This can sometimes happen if you made changes to a VC i.e. deleted prototype cell(s) within a tableview.

If all else fails I find cleaning project and restarting Xcode gets things back on track.

Answer 6

It looks like you deleted FirstViewController.h & .m from project, but forgot to change view controller's class in nib file.