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   

The following updates fix this issue; 

Updates that contain the issue are listed below. 

OS KB Number
RS1 - Windows 10 1607 and Windows Server 2016 4512517
RS2 - Windows 10 Version 17034512507
RS3 - Windows 10 Version 17094512516
RS4 - Windows 10 version 1803 or Windows Server Version 18034512501
RS5 – Windows 10 version 18094511553
19H1 (1903) – Windows 10, version 1903 4512508
TH1 (1507/RTM)4512497
Monthly Rollup Win 8.1 and Win Server 2012 R24512488
Sec. Only Win 8.1 and Win Server 2012 R24512489
Monthly Rollup Win Server 2012 & Windows Embedded 8 Standard4512518
Sec. Only Win Server 2012 & Windows Embedded 8 Standard4512482
Monthly Rollup Win 7 SP1 and Win Server 2008 R2 SP14512506
Sec. Only Win 7 SP1 and Win Server 2008 R2 SP14512486
Monthly Rollup Win Server 2008 SP24512476
Sec. Only Win Server 2008 SP24512491