What are the types of reports that an auditor can issue for an audit of ICFR? Briefly identify the circumstances justifying each type of report

Unqualified Report - provides reasonable assurance that the clients controls are designed and operating effectively in all material respects as of the balance sheet date
Adverse Report for a Material Weakness - The presence of a material weakness at the end of the period necessitates an adverse assessment by management and an adverse opinion by the auditor. An adverse report includes a definition of a material weakness and a description of the particular material weakness identified in the clients system of internal control, along with the auditors opinion that the client has not maintained effective ICFR as of the report date.
Disclaimer for Scope Limitation .The auditor can express an unqualified opinion on the effectiveness of ICFR only if the auditor has been able to apply all the procedures necessary in the circumstances. If the scope of the auditors work is limited because of circumstances beyond the control of management or the auditor, the auditor should disclaim an opinion or withdraw from the engagement.