Unfortunately, even changing the attachment limit in Outlook won’t necessarily mean it’ll work everywhere. If you’re using Outlook for a Gmail account, for example the 25 megabyte size limit will work in Outlook, but Gmail’s servers still won’t send it. For Exchange, self-hosted email servers, and a handful of others, it won’t be an issue.

  1. Open the Outlook desktop client. 2. Hit Windows key + R to open the Windows run dialog box.
  2. Type “regedit” and click OK.
  3. Select Yes on the pop-up that asks if it’s okay to make changes to your device.
  4. Navigate to one of the following keys in the registry tree (depending on your Office version).  Outlook 2010: HKEY_CURRENT_USER\­Software\­Microsoft\­Office\­14.0\­Outlook\­Preferences.Outlook 2013: HKEY_CURRENT_USER\­Software\­Microsoft\­Office\­15.0\­Outlook\­Preferences.Outlook 2016: HKEY_CURRENT_USER\­Software\­Microsoft\­Office\­16.0\­Outlook\­Preferences.
  5. Open the “MaximumAttachmentSize” value in the right pane (if it exists). If “MaximumAttachMentSize” does not exist, add it. To do that, click Edit > New > DWORD (32-bit) Value then rename the value to “MaximumAttachMentSize.”
  6.  Add a size limit (in kilobytes). If you enter zero (0) for the Value data, Outlook won’t set a limit on your images.
  7. Press OK and close the Registry Editor.

Microsoft Outlook Tips

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Block a Sender in Outlook 2016How to Instantly Mark Messages as Read in Outlook 2016 and PriorEdit New Message Alerts in OutlookHow to Mail Merge in Office 2016Set an Out of Office Reply in OutlookHow to Create Custom Groups in Outlook 2016Download Your Address Book in Outlook 2016 and PriorHow to Archive Mail in Outlook 2016Create an Email Signature in Outlook 2016 and PriorAttach a Calendar Event to an EmailSet Up a Universal InboxImport Contacts to macOS Address BookPurge Deleted MessagesDelete Addresses in Outlook AutocompleteImport Contacts via CSVBack Up Outlook DataChange Fonts in OutlookExport Contacts to CSVAdd an Image to Your SignatureSet Up Out-of-Office MessagesCreate Email TemplatesRestrict Notifications to Important Emails OnlyGet Read ReceiptsUse Two Time Zones for MeetingsRecall an EmailSave Common SearchesFilter EmailBlock Unwanted MailStop Sending Winmail.datAutomate Repetitive ActionsSchedule Outgoing MailCreate Canned Replies