OST files need to be converted to PST files to be opened in Outlook again.I have found many clients with years of data in these very unsafe OST files.I can fix this, but how I fix it is by moving out all large emails to a local PST file and remove some IMAP folders from being subscribed by Outlook. #4 Your email stops sending or receiving If you cap out with your email limits, your Outlook Gmail will stop sending or receiving or both.To solve this problem, you have to move a lot of email.
Check it out here As an Outlook Expert I get calls all the time from people who are suffering from slow Outlook, Outlook not working right, emails won't send or receive, emails are missing, folders are missing and many times they are using Gmail as their server.
If you want my help moving your entries to a safe PST file, we can schedule an appointment.
As of Dec 16, 2016 I updated a new blog now about "How to setup Gmail in Outlook" as there are so many security issues and people having problems getting through the security.
This issue is caused by installing one of the following updates that have been pushed out by Microsoft on 11/12/13: KB2837618 or KB2837643 If you have not already done so, please avoid this update for a bit until Microsoft corrects the issue.
If you cannot avoid the update, we will provide you with further steps regarding a temporary fix for the issue.