Missing file warnings showing up after upgrade to Xcode 4

These solutions are way too difficult. The problem is that you have removed the project from filesystem but SVN still thinks they are there.Detaching project from SVN will work, the same for removing .svn folders BUT that is going to destroy your repository!

It is much easier to open console, browse to your folder ("cd /pathToYourFolder") and type the following command:

svn delete nameOfMissingFile

If the name of your missing file includes the @ character (eg: retina-specific artwork), ensure the file name terminates with the @ symbol:

svn delete nameOfMissingFile@2x.png@

For GIT repositories:

git rm nameOfMissingFile

In XCode 4.2.+ (possibly in 4+) you can avoid manual work and command line :

1. Select project Project Navigator (Command - 1)
2. Choose File - Source Control - Commit menu
3. In the left pane, on top of it you have three icons, select the middle one - File view
4. You will see the list of all missing files
5. Select all of them and right-click - Discard changes. This will restore all deleted files from the SVN server and place them in your local SVN folder
6. Drag and drop those files into the XCode project (Choose Sort-Date Modified in Finder to easily find them)
7. Delete those files properly through XCode (select files and choose right-click Delete)
8. Commit the project

And that's it :)

All those nasty warnings are gone!

Additionally for Xcode 6+: After selecting the file view 'middle icon' - you can click the checkbox to the left and this will mark them as deleted for SVN when you next commit!

In Xcode5 & Xcode6, below steps worked for me

Xcode -> Preferences -> Source Control -> uncheck Enable Source Control

then

Xcode -> Preferences -> Source Control -> check Enable Source Control