Can't save project preferences in Eclipse

Question

All I am trying to do is to set the Java compiler for my project as 5.0. It is 1.4 by default. When I try to save by pressing OK button I get the following error.

Pr

Answer 1

If you follow this thread, this can be:

• because of the use of Eclipse with a workspace on a network drive (not necessarily your case, but worth mentioning just in case)
• because the file is somehow locked (either by another process or by a Version Control System with pessimistic locking). See also bug 130266:

Read-only project files come up a lot when dealing with source control systems (like Perforce) that make the local files read-only until they are "checked out".