Hello again, The "slow problem" has appeared again. Now we have debugged it and we have the FileMon (FileMonitor) log files where we can see what's doing Thunderbird when it works ok and when it works bad. When working bad (fragments): ============================= 16 11:26:12 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Options: Open Access: All 17 11:26:12 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Attributes: A 18 11:26:12 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS 19 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1 NAME COLLISION Options: Create Directory Access: All 20 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL NAME COLLISION Options: Create Directory Access: All 21 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP NAME COLLISION Options: Create Directory Access: All 22 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat NAME COLLISION Options: Create Access: All 23 11:26:12 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules-1.dat SUCCESS Options: Open Access: All 24 11:26:12 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules-1.dat SUCCESS Attributes: A 25 11:26:12 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules-1.dat SUCCESS 26 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1 NAME COLLISION Options: Create Directory Access: All 27 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL NAME COLLISION Options: Create Directory Access: All 28 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP NAME COLLISION Options: Create Directory Access: All 29 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP\tmprules-1.dat NAME COLLISION Options: Create Access: All 30 11:26:12 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules-2.dat SUCCESS Options: Open Access: All 31 11:26:12 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules-2.dat SUCCESS Attributes: A 32 11:26:12 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules-2.dat SUCCESS 33 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1 NAME COLLISION Options: Create Directory Access: All 34 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL NAME COLLISION Options: Create Directory Access: All 35 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP NAME COLLISION Options: Create Directory Access: All 36 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP\tmprules-2.dat NAME COLLISION Options: Create Access: All 37 11:26:12 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules-3.dat SUCCESS Options: Open Access: All 38 11:26:12 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules-3.dat SUCCESS Attributes: A 39 11:26:12 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules-3.dat SUCCESS 40 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1 NAME COLLISION Options: Create Directory Access: All 41 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL NAME COLLISION Options: Create Directory Access: All 42 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP NAME COLLISION Options: Create Directory Access: All 43 11:26:12 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP\tmprules-3.dat NAME COLLISION Options: Create Access: All 44 11:26:12 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules-4.dat SUCCESS Options: Open Access: All 45 11:26:12 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules-4.dat SUCCESS Attributes: A [...] 59342 11:26:28 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules-2689.dat SUCCESS 59343 11:26:28 thunderbird.exe:2372 CREATE C:\DOCUME~1 NAME COLLISION Options: Create Directory Access: All 59344 11:26:28 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL NAME COLLISION Options: Create Directory Access: All 59345 11:26:28 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP NAME COLLISION Options: Create Directory Access: All 59346 11:26:28 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP\tmprules-2689.dat NAME COLLISION Options: Create Access: All 59347 11:26:28 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules-2690.dat SUCCESS Options: Open Access: All 59348 11:26:28 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules-2690.dat SUCCESS Attributes: A 59349 11:26:28 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules-2690.dat SUCCESS 60790 11:26:31 thunderbird.exe:2372 OPEN D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Options: Open Access: All 60791 11:26:31 thunderbird.exe:2372 QUERY INFORMATION D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Attributes: 60792 11:26:31 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS 60793 11:26:31 thunderbird.exe:2372 CREATE D:\USUARIS NAME COLLISION Options: Create Directory Access: All 60794 11:26:31 thunderbird.exe:2372 CREATE D:\USUARIS\castell NAME COLLISION Options: Create Directory Access: All 60795 11:26:31 thunderbird.exe:2372 CREATE D:\USUARIS\castell\THUNDERBIRD NAME COLLISION Options: Create Directory Access: All 60796 11:26:31 thunderbird.exe:2372 CREATE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf NAME COLLISION Options: Create Access: All 60797 11:26:31 thunderbird.exe:2372 CREATE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Options: OverwriteIf Access: All 60798 11:26:31 thunderbird.exe:2372 WRITE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Offset: 0 Length: 4096 60799 11:26:31 thunderbird.exe:2372 WRITE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Offset: 4096 Length: 4096 60800 11:26:31 thunderbird.exe:2372 WRITE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Offset: 8192 Length: 4096 60801 11:26:31 thunderbird.exe:2372 WRITE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Offset: 12288 Length: 4096 60802 11:26:31 thunderbird.exe:2372 WRITE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS Offset: 16384 Length: 3223 60803 11:26:31 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\localstore.rdf SUCCESS When working OK: ================ 16 11:31:55 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules.dat NOT FOUND Options: Open Access: All 17 11:31:55 thunderbird.exe:2372 CREATE C:\DOCUME~1 NAME COLLISION Options: Create Directory Access: All 18 11:31:55 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL NAME COLLISION Options: Create Directory Access: All 19 11:31:55 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP NAME COLLISION Options: Create Directory Access: All 20 11:31:55 thunderbird.exe:2372 CREATE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Options: Create Access: All 21 11:31:55 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS 22 11:31:55 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Options: OpenIf Access: All 23 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Length: 0 24 11:31:55 thunderbird.exe:2372 WRITE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Offset: 0 Length: 27 25 11:31:55 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS 26 11:31:55 thunderbird.exe:2372 OPEN D:\USUARIS\castell\THUNDERBIRD\ImapMail\ SUCCESS Options: Open Directory Access: All 27 11:31:55 thunderbird.exe:2372 DIRECTORY D:\USUARIS\castell\THUNDERBIRD\ImapMail\ SUCCESS FileBothDirectoryInformation: bustia.fib.upc.es 28 11:31:55 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\ImapMail\ SUCCESS 29 11:31:55 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\ SUCCESS Options: Open Directory Access: All 30 11:31:55 thunderbird.exe:2372 DIRECTORY C:\DOCUME~1\CASTELL\TEMP\ SUCCESS FileBothDirectoryInformation: tmprules.dat 31 11:31:55 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\ SUCCESS 32 11:31:55 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Options: Open Sequential Access: All 33 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS FileAttributeTagInformation 34 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Length: 27 35 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Attributes: A 36 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS FileStreamInformation 37 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Attributes: A 38 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS FileEaInformation 39 11:31:55 thunderbird.exe:2372 CREATE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Options: Create Sequential Access: All 40 11:31:55 thunderbird.exe:2372 QUERY INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS FileFsAttributeInformation 41 11:31:55 thunderbird.exe:2372 QUERY INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Attributes: A 42 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS FileFsAttributeInformation 43 11:31:55 thunderbird.exe:2372 SET INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Length: 27 44 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Length: 27 45 11:31:55 thunderbird.exe:2372 WRITE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Offset: 0 Length: 27 46 11:31:55 thunderbird.exe:2372 READ D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Offset: 0 Length: 4096 47 11:31:55 thunderbird.exe:2372 SET INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS FileBasicInformation 48 11:31:55 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS 49 11:31:55 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS 67 11:31:55 thunderbird.exe:2372 OPEN D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\ SUCCESS Options: Open Directory Access: All 68 11:31:55 thunderbird.exe:2372 DIRECTORY D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\ SUCCESS FileBothDirectoryInformation: msgFilterRules.dat 69 11:31:55 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\ SUCCESS 70 11:31:55 thunderbird.exe:2372 OPEN D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\msgFilterRules.dat SUCCESS Options: Open Access: All 71 11:31:55 thunderbird.exe:2372 QUERY INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\msgFilterRules.dat SUCCESS FileAttributeTagInformation 72 11:31:55 thunderbird.exe:2372 DELETE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\msgFilterRules.dat SUCCESS 73 11:31:55 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\msgFilterRules.dat SUCCESS 74 11:31:55 thunderbird.exe:2372 OPEN D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Options: Open Access: All 75 11:31:55 thunderbird.exe:2372 QUERY INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS FileAttributeTagInformation 76 11:31:55 thunderbird.exe:2372 QUERY INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS Attributes: A 77 11:31:55 thunderbird.exe:2372 OPEN D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\msgFilterRules.dat SUCCESS Options: Open Access: All 78 11:31:55 thunderbird.exe:2372 SET INFORMATION D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\tmprules.dat SUCCESS FileRenameInformation 79 11:31:55 thunderbird.exe:2372 CLOSE D:\USUARIS\castell\THUNDERBIRD\ImapMail\bustia.fib.upc.es\msgFilterRules.dat SUCCESS 80 11:31:55 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\ SUCCESS Options: Open Directory Access: All 81 11:31:55 thunderbird.exe:2372 DIRECTORY C:\DOCUME~1\CASTELL\TEMP\ SUCCESS FileBothDirectoryInformation: tmprules.dat 82 11:31:55 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\ SUCCESS 83 11:31:55 thunderbird.exe:2372 OPEN C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS Options: Open Access: All 84 11:31:55 thunderbird.exe:2372 QUERY INFORMATION C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS FileAttributeTagInformation 85 11:31:55 thunderbird.exe:2372 DELETE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS 86 11:31:55 thunderbird.exe:2372 CLOSE C:\DOCUME~1\CASTELL\TEMP\tmprules.dat SUCCESS I'll attach the log files so you can review (load) it using FileMon. As we can see, when Thunderbird works properly (i.e. after deleting all tmprules*.dat in the Temp folder of the user), it creates, uses and DELETES tmprules.dat (see lines 85&86). But, when the problem happens (we don't why it starts) we can see that Thunderbird tries to create tmprules-x.dat files always starting by the first one until it can create a tmprules-x.dat file that doesn't exist. So, as the user works with Thunderbird, more and more files are created/checked, etc. This checking/creation process consumes a lot of CPU (100%) and Thunderbird doesn't respond to keyboard inputs of the user. Please, can someone check and solve this problem? Thank you very much. PS: Note that I can "mask" it by having the PC delete all these temporary files before the user logon but it's better to solve the problem in its root, isn'it?