Permissions on Mac OSX

I think that this is a permissions issue but I am not sure and I am not sure how to repair the problem.

I have a new MacBook. I have 2 external drives that were previously u开发者_如何学JAVAsed on another MacBook. I have a lot of folders and XCode projects on the external drives. When I try to work on the projects, there is a message similar to this:

"This file is not writable. You may not be able to save your changes, but you will be able to Save a Copy somewhere else. Do you want to edit this file anyway?"

If I make changes and try to close the project I get this error:

"The project and user files project.pbxproj and macbook.pbxuser for project “thirdtry.xcodeproj” are not writeable and cannot be saved. Your changes will be lost if you close the project. You may need to SCM edit these files to gain writability."

I have tried just to rename the folder but that permission is not allowed either unless I individually change permissions for every file in an XCode project. As you can imagine, this could be time consuming for tons of files and projects.

I can copy the project into internal memory and can run it then after renaming the folder that contains all of the files. This defeats the purpose of having all of the projects on an external drive.

Also, in XCode, there is no "Build and Run" there is only "Build and Debug" now. I don't know if this is related or not.

Suggestions for how to repair all permissions to all files and folders on my external drives? What about the "Build and Debug" and no "Build and Run" choice?

Thanks, Linda

You can Get Info on the external drive in the Finder and check "Ignore ownership on this volume". This will let you continue to use the drive on your other computer as before. If you no longer use the old machine, Paul's answer is a better solution.

The files and folders on the external drives probably have the wrong owner. You can easily rectify this via the command line using chown, e.g.

$ sudo chown -R myusername /Volumes/ExternalVolume/MyProjects/*

For documentation see:

$ man chown