I have two separate clients running Exchange 2013 and Outlook 2013 with the same issue. Neither can attach large attachments. I set the message size in the send connector to unlimited. But when I try to add large attachments it says "The File you're attaching is bigger than the server allows." I also increased all the receive connectors to 100mb to see if that would help and it didn't have an effect. There is also no message size restriction on the test account either. I also went and added the registry edit to remove any size restrictions for Outlook but that did not help either. I have been unable to find what in Exchange 2013 is cau

Did you check Organizational Limits? That's where it is being checked for the message what you are getting at the outlook level.

Reference: Message Size Limits

Size limit	Default value	Shell configuration	EAC configuration
Maximum size for messages received	10 MB	Cmdlet: Set-TransportConfig Parameter: MaxReceiveSize	Mail flow > Receive connectors > More options > Organization transport settings > Limits tab > Maximum receive message size
Maximum size for messages sent	10 MB	Cmdlet: Set-TransportConfig Parameter: MaxSendSize	Mail flow > Receive connectors > More options > Organization transport settings > Limits tab > Maximum send message size

• Marked as answer by Baron164 Friday, May 23, 2014 9:32 PM

Did you check Organizational Limits? That's where it is being checked for the message what you are getting at the outlook level.

Reference: Message Size Limits

Size limit	Default value	Shell configuration	EAC configuration
Maximum size for messages received	10 MB	Cmdlet: Set-TransportConfig Parameter: MaxReceiveSize	Mail flow > Receive connectors > More options > Organization transport settings > Limits tab > Maximum receive message size
Maximum size for messages sent	10 MB	Cmdlet: Set-TransportConfig Parameter: MaxSendSize	Mail flow > Receive connectors > More options > Organization transport settings > Limits tab > Maximum send message size

• Marked as answer by Baron164 Friday, May 23, 2014 9:32 PM

I set that setting up to 100mb and I still can't add any attachment over 25mb.

Did you just do that? It might take a while (up to couple of hours) to get updated the cache...

Ok, I'll give it a couple of hours and try it again.

Still doesn't want to work. I have closed and re-opened Outlook a few times. I did find that if I go into the mailbox settings of the user and manually set a limit of 100mb then I can add attachments that are larger than 25mb. But I'd rather not set the limit on an individual basis.

Correct, you don't really have to do that on individual basis that's override if you need to set higher limit than set at org level for only few users. Just wait for some more time.

• Edited by Amit TankMVP, Moderator Wednesday, May 14, 2014 7:32 PM

Correct, you don't really have to do that on individual basis that's override if you need to set higher limit than set at org level for only few users. Just wait for some more time.

• Edited by Amit TankMVP, Moderator Wednesday, May 14, 2014 7:32 PM

Ok, I'll give it some more time.

I am not sure about 2013 but in 2010 there is also a setting under hub transport in global settings -> transport settings that also specifies the maximum messages size.

I have also read where a restart of the transport service may be required after making changes like these.

Yes, worth a try restarting service, helps to release the cache.

Restarting the transport service did not help. It still won't let me add large attachments. I know about the global settings in 2010, unfortunately those settings are MIA in the 2013 ECP.

You are also going to have to increase the  message size on the computer running  Outlook 2013

https://support.microsoft.com/kb/2813269?

• Proposed as answer by Kirk.wetzel Tuesday, January 13, 2015 8:47 PM
• Edited by Kirk.wetzel Tuesday, January 13, 2015 8:58 PM

You are also going to have to increase the  message size on the computer running  Outlook 2013

https://support.microsoft.com/kb/2813269?

• Proposed as answer by Kirk.wetzel Tuesday, January 13, 2015 8:47 PM
• Edited by Kirk.wetzel Tuesday, January 13, 2015 8:58 PM

Hello there!

Same problem with Exch 2013 and Outlook 2013, i've increased limit in both transports at Exch & done https://support.microsoft.com/kb/2813269 registry changes at 2 different clients. 

After many reboots of server & clients & rain dances still got "the file you're attaching is bigger than the server allows...".

Is anyone solved this problem?

Fixed it!)

Problem was in send connector - from GUI it was changed OK & shows what i say, but from

Get-SendConnector | ft name, MaxMessageSize

it shows earlier mark. So i did

Set-SendConnector <Connector Name> MaxMessageSize 50MB

and after some hours everyone was happy bout that.

Thanks!)