Home > Support Articles > Calendar Sync > Why does CiraSync take so long to sync my contacts and calendars?

There are multiple factors that can affect CiraSync performance. These include the following:

  • Number of mailbox in a tenant
  • Amount of updates that need to be made
  • Type of data that needs to be written in
  • Current performance of Exchange Web Services (EWS)

Below are steps you can take to speed up CiraSync sync tasks:

  1. Set up your CiraSync tenant to use multiple service accounts.
  2. Enable the CiraSync streamer in the Schedule pane of the CiraSync dashboard if the sync source is a shared mailbox or a Public Folder. CiraSync will then periodically read the source and then sync any changes found to user mailboxes. 
    NOTE: Unfortunately, CiraSync has no control over the performance of EWS, and no workaround exists to improve its performance.