You can do that by going to File, then Data Management. Compact your PST file every once in awhile. Empty your spam folder and your trash folder often. Empty them out! Someone like me gets hundreds of spam emails a day! That’s all stored in the Outlook database and slows it down. For some reason, people forget about their spam and trash folders. You can use Google Calendar for any Internet calendars you want to follow. Outlook just wasn’t designed to handle RSS feeds all that well, so anything more than a couple will slow down Outlook.
Yes, Google Reader was great and now that it is gone, why not use Outlook to manage your feeds right? Bad idea! There are still many good online and offline RSS readers that you can use other than Outlook. Rule 4. Use a different program for RSS feeds and Internet calendars. Under User Settings, uncheck the Review documents and mail to improve accuracy option. You can go to Control Panel, Speech Recognition and then click on Advanced Speech Options. It will also prevent your system from scanning your emails, etc. If you don’t use this, disable it so that it doesn’t load every time Outlook starts. Outlook comes bundled with the Speech and Handwriting Recognition features that are a part of Windows. Another window will popup and you can uncheck the items you don’t want. To actually disable an add-in, you have to select COM Add-ins in the combo box at the bottom and click Go. If you don’t use them, get rid of them! They have to be loaded into memory when Outlook is started and they make the program slower also. Even Microsoft adds a bunch of stuff that I normally disable like Skype, OneNote, SharePoint, etc.
A lot of programs love to install add-ons to Outlook automatically, such as Adobe, EverNote, Wunderlist, etc. Make sure you are only using essential add-ins for Outlook.
If you don’t want to do that, at least move all older emails to another folder so that Outlook does not have to load thousands of emails every time it comes to the Inbox, thus causing higher memory usage. That’s why it’s a good idea to turn on AutoArchive because it will take care of it automatically without any intervention. It’s also worth noting that you have to do this for each mailbox you have setup in Outlook. Also, make sure to empty out the deleted items folder afterwards as that still takes up space. I would check the mailbox size and if it’s anything over 500 MB, you should turn on AutoArchive or delete any emails that are taking up a large amount of space. You’ll see several options as shown below. Click on File and then click on Tools and then Mailbox Cleanup.