here are how you can increase size of attachment in MS CRM. by default it is 5mb.
1. Open the web.config of MS CRM
2. Locate httpRuntime the
httpRuntime executionTimeout="9999" maxRequestLength="10240"
3. Locate httpRuntime the
save the web.config and restart IIS.
msn : firstname.lastname@example.org
skype : mscrmexpert