RT Error -2147467259 - Presentation (unknown member) ...

[Barb Reinhardt]

I'm running a macro out of Excel 2007 that opens and manipulates a bunch of
PowerPoint presentations. It's worked for quite a while and today, I'm
getting this error

Run-time error '-2147467259 (800004005)':

Presentation (unknown member) : Invalid request. Automation rights are not
granted.

The line I get this error on is this (very much abbreviated code, but shows
the error)

For Each myPPT In PPTApp.Presentations
debug.print myppt.path '<~~error here for first time through loop.
Next myPPT

PPTApp.Presentations.Count = 23, but I only see 22 presentations that it's
working on. Where is the mystery presentation?

I've found a workaround, but this just started and I'm interested to know why.

Thanks,
Barb Reinhardt