Set a local mailbox size with GWSMO


You want to set a local mailbox size with GWSMO cause you notice that the mailbox size is set to unlimited, but is not working correctly.


  • Microsoft Outlook
  • Google Workspace Sync for Microsoft Outlook (GWSMO)


  1. Click GWSMO in your Microsoft Windows taskbar notification area.
    1. The GWSMO icon appears in the notification area, typically next to the clock. This area has been known historically as the system tray. From here, you can open the GWSMO settings.
    2. If you cannot find the icon, it might be automatically hidden within the overflow area. To view all icons, click the up arrow on the taskbar.
    3. Note: The icon only appears if GWSMO is running.
  2. Choose Set mailbox size limit.
  3. Select a mailbox size from the dialog that opens. Your size options are 1 GB, 2 GB, 4 GB, or Unlimited. Note that depending on your computer, a larger size might degrade performance when searching and indexing.


Does the Unlimited size option really mean unlimited? No. By default, Outlook limits the size of a local PST file to 20 GB (for Outlook 2007) or 50 GB (for Outlook 2010, 2013, 2016, or 2019). So, if you choose the Unlimited mailbox size in GWSMO, your PST file won't exceed 20 GB or 50 GB. To increase the limit of your PST file, consult your Microsoft documentation.
Note: If you decide the Unlimited mailbox size in GWSMO and your PST file grows larger than your default Outlook limit, you might encounter sync errors. In addition, large PST files can create performance problems.