java.lang.IllegalStateException: Cannot generate build scripts from a modified project
        at org.netbeans.spi.project.support.ant.GeneratedFilesHelper$2.run(GeneratedFilesHelper.java:579)
        at org.netbeans.spi.project.support.ant.GeneratedFilesHelper$2.run(GeneratedFilesHelper.java:576)
        at org.openide.util.Mutex.readAccess(Mutex.java:327)
        at org.netbeans.spi.project.support.ant.GeneratedFilesHelper.getBuildScriptState(GeneratedFilesHelper.java:576)
        at org.netbeans.spi.project.support.ant.GeneratedFilesHelper$3.run(GeneratedFilesHelper.java:804)
        at org.netbeans.spi.project.support.ant.GeneratedFilesHelper$3.run(GeneratedFilesHelper.java:802)
        at org.openide.util.Mutex.writeAccess(Mutex.java:433)
        at org.netbeans.spi.project.support.ant.GeneratedFilesHelper.refreshBuildScript(GeneratedFilesHelper.java:802)
        at org.netbeans.modules.java.j2seproject.J2SEProject$ProjectOpenedHookImpl.projectOpened(J2SEProject.java:521)
        at org.netbeans.spi.project.ui.ProjectOpenedHook$1.projectOpened(ProjectOpenedHook.java:81)
        at org.netbeans.spi.project.ui.support.UILookupMergerSupport$OpenHookImpl.projectOpened(UILookupMergerSupport.java:193)
        at org.netbeans.spi.project.ui.ProjectOpenedHook$1.projectOpened(ProjectOpenedHook.java:81)
        at org.netbeans.modules.project.ui.OpenProjectList.notifyOpened(OpenProjectList.java:1059)
        at org.netbeans.modules.project.ui.OpenProjectList.doOpenProject(OpenProjectList.java:1110)
        at org.netbeans.modules.project.ui.OpenProjectList.doOpen(OpenProjectList.java:663)
        at org.netbeans.modules.project.ui.OpenProjectList.access$1200(OpenProjectList.java:122)
        at org.netbeans.modules.project.ui.OpenProjectList$3.run(OpenProjectList.java:553)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:573)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1005)