Cannot Add Attachments Using the SmarterMail Web Interface

Sometimes end users may be unable to attach files to emails they send through the webmail interface. This can be resolved in a few short steps. 

First, verify that the permissions on the App_Data folder are set correctly. To verify the permissions, do the following:

1. Using the Windows Explorer, right-click the default folder C:\Program Files (x86)\SmarterTools\SmarterMail\MRS\App_Data directory.
2. Select Properties and then click the Security tab.
3. Select Network Service and make sure that Modify is checked and then click Apply and OK.
4. Log in to SmarterMail as the end user and verify attachments are now working properly.

Another possible cause for this problem is that disk quotas have been enabled on the Network Services Account and it has reached its limit. If so, disable disk quotas on this account and then once this is done retry sending an attachment to see if it's successful.