Slow Sync by first start
I have a test enviroment for the migration to Outlook with Active Sync.
Some users have huge mailboxes. The first sync is very slow. Can I increase the download speed? Why is the download so slow?
What is huge in your case? 1GB mailbox? 10GB? 100GB?
Which KC, Z-Push and KOE versions are you using?
The ActiveSync protocol wasn’t designed to sync GBs of data. It happens per request basis and max 512 items will be synced in one request. It takes processing time on the server and on the client.
The download speed is probably the least issue (unless the network connection between the computer with Outlook and server is really slow). You could try to use better hardware to increase sync, especially on the client side.
Also, if you don’t necessarily need all the emails in Outlook, you could limit the sync period to 1 month.
It also might depend on the number of syncs running in parallel. When switching to kopano, we always had several syncs running and a 10 GB mailbox took a night for the initial sync. Now I had to resync a 14 GB mailbox in normal operation and this took about 2 hours.