This bug was originally marked as duplicate of bug 205001, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE 7.2.1 (Build 201210100934)
VM: Java HotSpot(TM) Client VM, 17.1-b03, Java(TM) SE Runtime Environment, 1.6.0_22-b04
OS: Windows XP
GUEST: Netbeans is just endlessly 'scanning' the project at 100%, and eating up a lot of cpu
org.openide.filesystems.FSException: Cannot rename file Modules/.nbattrs~ in C:\Documents and Settings\john.fo\Application Data\NetBeans\7.2.1\config to Modules/.nbattrs. New file exists: false. Rename result: false.
Created attachment 133822 [details]
Only one report from older release 7.2.1.
The file couldn't be probably really deleted due to some filesystem problem,
or the system was under heavy load (maybe scanning, maybe some external process).
I cannot reproduce the problem, closing for now. If you can provide additional information, please reopen. Thank you.