Exchange Scenarios configured to create Outlook test folders are causing a collection of folders in a user's mailbox. This is due to synchronization issues caused by the user's Outlook client running while the Exchange scenario is executed. Less often, database corruption causes this issue.
This article provides recommendations for Exchange scenarios solving the issue and possible workarounds.
Symptoms
- The configured user's mailbox for the Exchange scenario has a collection of test folders.
How to Solve the Issue
We recommend running Exchange scenarios using a test mailbox as an entry point. Even though all actions are performed seamlessly and cleared once executed, we recommend dedicating a specific mailbox to avoid impacting any user.
This unexpected behaviour is observed only when using an Outlook client configured with cached Exchange mode enabled.
Possible Workaround
There are two options available if you need to open the Mailbox configured for Exchange scenarios:
Option 1: Use Outlook Web App (OWA) to access the mailbox content.
Follow this Microsoft Technet article to learn information about OWA.
Option 2: From the Outlook client, disable Use Cached Exchange Mode. 
Follow this procedure from the Microsoft Office support website to turn off cached Exchange mode.
If the Quota of the mail box is reached due to the recovery folder being full, this will then prevent any folders being deleted. The solution is to disable recovery retention.