Most of the times, Outlook stops responding due to a very large mailbox file that it's causing Outlook to require more resources than the computer can offer.Weight Diet for Outlook can restore your Outlook speed and stability by decreasing & compacting your mailbox file, making Outlook to require less resources.Solution: While performing an autoarchive or syncronization job, it is advisable to allow Outlook to finish the task without inputing new actions.
Here are the most common reasons why Outlook may stop responding, popping up the annoying "end process" window or simply responding very slow to your input.
First of all, before looking for a complicated solution, try to optimize your Outlook mailbox using an optimization add-in such as Weight Diet for Outlook.
After the latest round of Office 2013 updates, some IMAP users are reporting their Inbox is not listed in their profile, is empty, or their IMAP accounts aren't syncing.
This is the result of the November 12 updates, KB2837618 and KB2837643.
Even so, the IMAP send/receive process is slower than the regular POP3 send/receive process.
Scenario: The more emails you receive and store, the greater the Outlook mailbox file.
Solution: Configure your anti-spam or anti-virus software to match your other Outlook add-ins, so they don't create security conflicts.
Add to the trusted executables list of your security / protection software.
Scenario: By default, Outlook is configured to automatically archive Inbox emails, so your mailbox file gets decreased.