Outlook 2007/2010–Some basic advice if you experience odd behaviour, startup latencies, calendar item losses …

•On an Outlook station of a user who complains about Outlook startup latencies :


–From the file-level antivirus on the desktop/laptop, Exclude files present

  • in the following directories (whichever is applying to your Windows version (Windows XP, Windows Vista or Windows 7)
  • %userprofile%Application DataMicrosoftOutlook (Outlook system files)
  • %userprofile%Local SettingsApplication DataMicrosoftOutlook (Windows XP/Vista, shortcut to “AppDataLocalMicrosoftOutlook” on Windows 7)
  • %userprofile%AppDataLocalMicrosoftOutlook (Windows 7 location)

->Or exclude *.nk2, *.dat, *.srs, *.xml, *.otm, OutlPrnt, *.ost, *.ost.tmp, *.obi and *.oab files from these directories.

Note 1: if you don’t want to exclude the whole *.xml extensions, which is understandable, you can just exclude the Policy*.xml and *autodiscover.xml files only.

Note 2: If you still are reluctant about excluding too many files, the following have to be excluded anyways or sooner or later you WILL be exposed to OST or OAB corruption,Outlook cached mode having more latencies that Outlook Online mode, or Calendar meetings being corrupted or simply not updated for you: *.OST, *.PST, *autodiscover.xml, policy*.xml, *.ost.tmp, OutlPrnt, and *.oab 


  • Exclude all PST files that the user uses (*.pst)

-> or the best option is to plan to replace the use of PST files by the Exchange 2010 personal archiving feature (to be discussed with the IT team)


– Check the startup time without any Add-Ons (disable or uninstall them all, and if not possible, open an Outlook profile on an other “neutral” desktop/laptop with a simple Outlook client – without add-ons installed)

• If without add-ons there are no more latencies, then add the add-ons one by one and restart Outlook until you see the latencies to identify a potential guilty add-on.


– If no add-ons are causing the issues, take and analyse a network trace on the Outlook workstation

•Check for dropped network frames

•Check for client/server disconnections ([RST] or [ACK, RST])

•Check for proper server connection (i.e. outlook is not trying to reach other servers before reaching the final one)


–If nothing it noticed on the Network trace analysis, take an outlook application trace and check if there is an issue with the application installation itself (Outlook troubleshooting mode in the advanced options)

– Outlook troubleshooting mode useful files :

> The Outlook troubleshooting transport log file %UserProfile%AppDataLocalTempOutlook loggingOpmlog.log
> The application and system event logs from the Laptop having the issue in both CSV and EVTX formats.
> the Application and System event Logs from the machine where the problem has been reproduced:

– All the following from the %TEMP% directory :


o The oldisc.log file

o The logcalb2 file

o The “Outlook logging” subdirectory (there will be a couple of text files inside)

o The OlkCalLogs subdirectory

Comments (2)

  1. Anonymous says:

    Thanks for this useful article ! That’s a good place to start as before we had no idea what to do !

  2. Anonymous says:

      > Plan antivirus scanning for Outlook 2010