The maximum size of attachment and import files that can be uploaded to the server can be configured with the settings:
"MaxFileUploadPackageSize" which sets the maximum size of files that can be uploaded. Below the max size is 2 Mb.
"MaxFileUploadPackages" which sets the maximum number of chunks the file will be sent in. Below the value is 4.
With the configuration below, a 1 Mb file would be sent in two chunks of 500 Kb.
If you send a file exceeding the size limit, you will get this error message:
If none of the settings exists in the web.config file, "MaxFileUploadPackageSize" defaults to 2147483647 and "MaxFileUploadPackages" defaults to 100000.