Altium Unable to cast COM object type

Summary

This blog describes how Altium users can resolve the "Unable to cast COM object type" which can be caused as a result of installing / uninstalling Office (32 bit) software together with Office (64 bit).

Altium Dialog Message

The "Unable to cast COM object type" message can be displayed when there is a requirement for Altium to use Excel libraries, such as generating a Bill of Materials (BOM).

Altium Dialog Message

The message identifies a registry entry which is located at HKCR\TypeLib.

Causes

One Microsoft blog explains that the message may be displayed within Office applications when a mixture of Office 32/64 bit applications are installed on the same machine. The Microsoft blog suggests removing the HKCR key 

00020813-0000-0000-C000-000000000046 although applying this change with Altium did not resolve the issue.

Registry 00020813-0000-0000-C000-000000000046 Entry

Office Repair

To remedy the issue in Altium, an Office Repair was required. With the Altium application closed, may not be necessary, the Apps and Features application was opened from the 'Start' menu and the relevant Office installation selected.

Windows 10 Apps and Features

The Modify button was selected followed by the Quick Repair.

Office Quick Repair

Quick Repair Started

In a few minutes the repair finished.

Quick Repair Finished

After the repair Altium was launched and a BOM generated without any issues.

Other Altium Messages

While replicating the "Unable to cast COM object type" Altium message for this blog, the process of installing 32 bit Office software did interfere with another Microsoft redistributable. This resulted in Altium displaying a dialog detailing the missing redistributable. Fortunately the Altium dialog provided a link to the Microsoft website where an installation of the redistributable resolved the issue.

Altium kb4041681 JET database fix for unexpected error

Summary

This blog illustrates how Altium users may be able to resolve the issue created by Microsoft KB4041681, which causes a problem with JET databases in Altium: “Unexpected error from external database driver (1). (Microsoft JET Database Engine). This results in Altium being unusable - until the Microsoft update is rolled back.

Microsoft Updates
As part of Microsoft's October patch and rollout, changes were made breaking the long deprecated JET database. This has been tracked in numerous blogs such as blogs.msdn.microsoft.com. For Altium Dblib users the recommended change was mentioned in the KB4041681 release. There are two methods suggested below for resolving the issue in Altium.

My Windows 10 work computer is connected to a domain and ergo a group policy. Permanently blocking KB4041681 is not a reasonable solution when a group policy is applied to each computer, however for a Altium system originally built on Protel 99, this is fixable.

Users Dblib file

To start the process, Altium is launched and the appropriate Dblib file located and opened.

Just beneath the source of connection section in the Altium dialog box, the JET database error message is shown.

Altium JET database error

For the methods listed below users should use the appropriate link in place of the text <my Altium excel file>.

Method 1: Changing to Excel 2007
As highlighted by the helpful folks on the EEVBlog forums the file type can be changed to Excel 2007. Older systems such as mine used Excel 2003. Changing is achieved using the drop down list box, as shown below, "Select Database Type" from Microsoft Excel to Microsoft Excel 2007.

Setting for Excel file

Any associated Excel files(s) would need to be saved in the new .xlsx format.

Setting for Excel 2007 file

Method 2: Changing from JET

The second method changed the database. This can my ascertained by reading the Microsoft 'kb' release which states "Download and install the Microsoft Access Database Engine 2010 Redistributable, and then modify the DB connection strings in Microsoft Excel to use ACE as a provider. Example: Change Provider=Microsoft.Jet.OLEDB.4.0 to Provider=Microsoft.ACE.OLEDB.12.0."

The connection type is changed by selecting "Use connection String" instead of "Select Database Type".

Connection string for JET in Altium

This connection string however, uses the older JET database so the Microsoft.ACE.OLEDB.12.0 is used to replace the Microsoft.Jet.OLEDB.4.0. The provision is that the database engine redistributable listed by Microsoft is installed.

Connection string for ACE in Altium

At the same time the Excel file is saved as the newer format ".xlsx".

Testing
After saving the updated Dblib file, Altium was launched again. There were no immediate issues placing components in the schematic.

This is by no means the solution for all Altium users. The methods listed in this blog has been tested briefly on a Win 10 Pro machine running Altium 17.1.6 with all Windows updates applied.

Addendum
During testing of the solution listed above, some users noted an additional OLE related exception shown by Altium. A window similar to the image below was displayed when trying to connect to the database.

Altium database OLE exception

This is a known issue that has been documented by a number blog sites such as PCBParts. If an Altium Database File of type DbLib is being used, opening the file from within Altium may show a similar image to that shown below. 

First step is to backup the DbLib file. 

Altium database connection failed

The second step, install an Office 2007 System Driver as provided from the PCBParts blog. This is one known fix.

After installation of the Office 2007 driver two results were reported. Either no further issues were seen or the Altium Database File was overwritten such that previous information about the database structure was removed - fixed by copying the DBLib file backup from the first step.