Outlook is very slow attaching files to email

I really hate this.  Outlook is running fine otherwise, however, when I try to attach a file to an email the process slows to a crawl.  Frustrating!!

First, try to run Outlook in Safe Mode.  Click Start and then Run, (Win7), or use Cortana, (Win10), and type Outlook /Safe and hit Enter.  If necessary, choose your profile, (usually Outlook), and click Ok.  Now try to attach a file in this mode.  If it works fine then you will need to disable add-ins.

To disable add-ins, restart Outlook in normal mode.  Then click File, then Options.  Then click the Trust Center and look for your add-ins.  Click Com add-ins.  Select the check boxes to clear the add-ins and try attaching the file again.