After resolving the immediate issue (reactivating server credentials), verifying system functionality ensures the solution works as intended and the user can now access the shared drive. This step is a part of the CompTIA troubleshooting methodology: * Identify the problem. * Establish a theory of probable cause. * Test the theory to determine the cause. * Establish a plan of action. * Implement the solution. * Verify full system functionality. * Document findings, actions, and outcomes. * Why Not B (Document the findings): Documentation comes after verifying the system works. * Why Not A (Escalate the issue): Escalation is unnecessary since the problem was resolved. * Why Not C (Perform backups): Performing backups is unrelated to verifying credential functionality. CompTIA A+ Exam Reference: Core 2 (220-1102), Section 3.1, troubleshooting methodology.