The SOLABS Unique ID is a unique identifier attributed to each user of a SOLABS QM instance.
For versions prior to 10.8.0, it was used to access the SharePoint Portal (where SOLABS QM Reports can be found) the Password Management Portal (where a user can change or reset her password) and the eRoom (where documentation is shared between SOLABS and its customers).
From 10.8.0 and going forward, following the SSO implementation in SOLABS QM's services, the SOLABS Unique ID is now only used to access the eRoom. All other services are now accessible with the username used to access SOLABS QM.
The SOLABS Unique ID can be found in the User Account Information page that is accessed directly when clicking on the Setup section's link, or when clicking on the User Account Information link under the Configurations topic in the Preferences tab of the Setup section's dashboard.
(Note that it is recommended to always use the SOLABS Unique ID from the Production instance.)