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.