Applicable Versions: All

A Microsoft update was released on 13th August that contained a change in the oleaut32.dll to mitigate a specific security exploit. Unfortunately, this mitigation unexpectedly caused any VBA and VB6 apps that passed an empty ParamArray to receive E_INVALIDARG in return from an internal function call.  This bubbles up to the error seen in the Report Designer.

In reply to this issue, a senior MS Engineer has responded "We are taking this very seriously and discussing the possibilities for a safe and quick way to resolve this. Since it was caused by a security update, there may be some obstacles to simply reverting the changes we made. Nevertheless, our full attention is on this issue now, and please rest assured that we will provide an update when we can safely do so."

As of 10am GMT on 19th August 2019, it appears Microsoft are already rolling out updates to fix the issue. As such, first try installing the latest available Windows updates on your machine. If that doesn't solve the issue, you will need to remove the offending KB until the appropriate update is available from Microsoft. 

For a complete list of MS Updates appropriate for your OS, please see https://aka.ms/WIndowsReleaseHealth   

The following updates fix this issue;

https://support.microsoft.com/en-gb/help/4512534/windows-10-update-kb4512534 

https://support.microsoft.com/en-gb/help/4512494/windows-10-update-kb4512494 

https://support.microsoft.com/en-gb/help/4512474/windows-10-update-kb4512474 

https://support.microsoft.com/en-gb/help/4512495/windows-10-update-kb4512495 

https://support.microsoft.com/en-gb/help/4517276/windows-10-update-kb4517276 

https://support.microsoft.com/en-gb/help/4517298/windows-8-1-update-kb4517298 

https://support.microsoft.com/en-gb/help/4517302/windows-server-2012-update-kb4517302 

https://support.microsoft.com/en-gb/help/4517297/windows-7-update-kb4517297 

Updates that contain the issue are listed below.