Generally, when users set up IMAP, the biggest complaints focus on the initial syncing from the server in-box to the user's in-box, often taking an extended period while the 1,000's of emails on the server are transferred to Outlook. This is completely avoidable and for many entirely unnecessary. A lot depends upon how often the users rely on indexed emails for reference purposes. If you aren't continually looking in old emails for attachments or contact info, then here's an easy fix.
When following the initial setup steps within Gmail, do the following:
settings icon (upper right corner of your email inbox screen and click to bringi up the drop-down ---> Settings. This will open up the gmail settings page. Go to the tab that reads Forwarding and POP/IMAP.
This is where you can determine whether changes made from within outlook are carried out on the server or if they are unique to your instance of outlook.
enble IMAP = ON
next, if you want to keep a copy on gmail even if you delete the message in Outlook, just change the auto-expunge option to "Off"
When I mark a message in IMAP as deleted:
Auto-Expunge on - Immediately update the server. (default)
--> Auto-Expunge off - Wait for the client to update the server.
next, determine HOW you want the info treated in GMAIL once you delete in Outlook (see below)
When a message is marked as deleted and expunged from the last visible IMAP folder:
Archive the message (default)
Move the message to the Trash
Immediately delete the message forever
The final option is where you can limit the number of emails that are downloaded to Outlook. Depending upon the volume of email you receive in your gmail account, pick whichever will allow you to interact with historical data while balancing against ahving to download 50k emails into oulook (which will slow your machine a LOT in the beginning as it attempts to index all of this information). For most, limiting the number of IMAP emails to 1,000 will do the trick. Hope this helps.