You can use SBM System Administrator to increase your attachment file size. Go to "Settings" and under the "Attachments" tab, there is this "Maximum File Size" option for you to set the size you need.

that looks like the file attachment via the actions dropdown / add file attachment. does this also apply to the Field File Attachment? 

It doesn't hurt to try and find out in this case if you have a development or test environment to test.

500 is the largest amount available. is there a way to allow larger? 

Sorry, I really don't know. You can also check with your DBA.

You will need to coordinate your attachment size with the Maximum request content length set in IIS.  See Configuror > IIS Server.  My value is set at a very low value.  The new default is 500MB.

Mine is already set to 500. what are my options for larger than 500 MB? 

The max. value is 4294967295 bytes (4 GB).  SBM would see this as 4000MB.

How large of a file would you like to upload?  Set this to that size.

thank you. I will set this setting to that, and see if I have any issues.