Case Status to Change when Customer Updates the Case
Under Setup > Support > Support Preferences > General tab > Preferences section, Messages Reopen Closed Cases is checked. However, when Case Status is set to Awaiting Customer Reply (custom status) and the Customer updates the Case by sending an email, the Case Status does not change to Re-Opened. Note: Default for Status for Reopened Cases is Re-Opened.
To resolve this, perform the following steps:
1. Navigate to Setup > Support > Case Statuses.
2. Edit the Status (e.g. Awaiting Customer Reply).
3. Set Stage to Closed.
4. Click Save.
Note: Issue#140147 has been created as an Enhancement Request for the ability to change the status of an open case on receiving customer email.