We have on occasion encountered issues with TCBI where the recommended fix is to delete TCBI user accounts and then let the program re-sync them. Sometimes this has been done in conjunction with an upgrade of the TCBI code.
The issue: if the user(s) are owners of any dashboards, then those dashboards also get deleted.
PRIOR TO removing any TCBI user accounts, the report owner must export the dashboards as DASH files to back them up. Then after the accounts have been recreated, the dashboards have to be re-imported and re-shared with the appropriate users. If this step is not taken, the dashboards will be lost.
PLEASE NOTE: this step is not a normal part of the upgrade process. A typical TCBI upgrade should not include removing user accounts, and therefore dashboards should remain in tact. However, it is always best practice to back up all dashboards prior to any upgrades, in case of problems.
The action of removing user accounts as a way to resolve issues should therefore only be done if absolutely necessary.
You can find instructions here to Import your dashboards.