Here is one another stack showing access to file system from EDT. In this particular case it was remote "AWT-EventQueue-1" prio=3 tid=0x08aca800 nid=0x1e runnable [0xbdffd000] java.lang.Thread.State: RUNNABLE at org.netbeans.modules.remote.impl.fs.RemoteDirectory.refreshDirectoryStorage(RemoteDirectory.java:476) at org.netbeans.modules.remote.impl.fs.RemoteDirectory.postDeleteChild(RemoteDirectory.java:170) at org.netbeans.modules.remote.impl.fs.RemoteFileObjectBase.deleteImpl(RemoteFileObjectBase.java:315) at org.netbeans.modules.remote.impl.fs.RemoteFileObjectBase.delete(RemoteFileObjectBase.java:270) at org.netbeans.modules.remote.impl.fs.RemoteFileObject.delete(RemoteFileObject.java:433) at org.netbeans.modules.cnd.discovery.buildsupport.CompileSupport.remove(CompileSupport.java:118) at org.netbeans.modules.cnd.makeproject.spi.configurations.CompileOptionsProvider$Default.remove(CompileOptionsProvider.java:116) at org.netbeans.modules.cnd.makeproject.ui.customizer.MakeCustomizer$MyListEditorPanel.removeAction(MakeCustomizer.java:726) at org.netbeans.modules.cnd.makeproject.ui.customizer.MakeCustomizer$MyListEditorPanel.removeAction(MakeCustomizer.java:681) at org.netbeans.modules.cnd.utils.ui.ListEditorPanel.removeObjectAction(ListEditorPanel.java:689) - locked <0xc495b270> (a org.netbeans.modules.cnd.makeproject.ui.customizer.MakeCustomizer$MyListEditorPanel) at org.netbeans.modules.cnd.utils.ui.ListEditorPanel.removeButtonActionPerformed(ListEditorPanel.java:711) at org.netbeans.modules.cnd.utils.ui.ListEditorPanel.access$700(ListEditorPanel.java:64) at org.netbeans.modules.cnd.utils.ui.ListEditorPanel$5.actionPerformed(ListEditorPanel.java:448) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236) at java.awt.Component.processMouseEvent(Component.java:6263) at javax.swing.JComponent.processMouseEvent(JComponent.java:3267) at java.awt.Component.processEvent(Component.java:6028) at java.awt.Container.processEvent(Container.java:2041) at java.awt.Component.dispatchEventImpl(Component.java:4630) at java.awt.Container.dispatchEventImpl(Container.java:2099) at java.awt.Component.dispatchEvent(Component.java:4460) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168) at java.awt.Container.dispatchEventImpl(Container.java:2085) at java.awt.Window.dispatchEventImpl(Window.java:2478)