Problems with LINKED EXCEL CHARTS in PowerPoint
AKA: Everything You Were Afraid To Ask Brian Reilly About Excel Charts, But That's OK, 'Cause He's Gonna Tell You Anyway. Actually, much of the content here originally was contributed to Brian by Naresh Nichani, an Access MVP, who is the real code writer behind Brian..
We now turn the microphone over to Brian Reilly, PowerPoint MVP, who bares all (and grins it)
Here's a fairly extensive list of things that happen with Excel linked charts to PPT and what you can do about it.
1 - It is best to put the charts on their own chart sheet. Better if you create custom size chart pages in Excel so you don't have to resize the devils in PPT.
2 - The reason behind the chart sheet approach vs. worksheets is that the size information seems to be somehow embedded in the upper left hand corner of the chart. Now, that upper left hand corner is always "visible" to the linking mechanism during update links since a chart sheet is 100% "visible". Now a worksheet may not be 100% "visible" if you stuck the charts all over the place in a worksheet. So, the update link mechanism looks at the worksheet and looks for the upper left hand corner of the chart for the size info. Now, stay with this one, it splits into two thoughts now.
a) if the "upper left hand corner of the chart is not visible" in what would be the ActiveWindow of the spreadsheet (if it were open), the update linker won't see it and may not update the chart, or worse, may chop off part off the chart image. Worse than a bad hair day, that feeling.
b) the second issue is the ActiveWindow zoom factor, if you are really going to insist on putting charts on worksheets (more on that later). If the chart was created at a zoom factor of "x" and the zoom factor of the worksheet is set to other than "x" when the file is saved and closed, then Excel linked charts will resize on you. I've gotten around this by creating a simple Auto_Close macro in Excel that sets the zoom factor back to 100% and saves and closes the file. Then the charts don't resize in PPT when the links are updated.
3 - If you do use the Chart sheet approach, make sure the option (Tools, Options, Chart, "Chart sizes with window frame" is NOT checked. It generally isn't by default I believe.
4 - Alright you say, but I got my data on the worksheet, the only way I can make sure the chart makes sense is when I see the chart next to the data (a someone valid argument). So make the chart on the chart sheet (didn't we just agree on that?
5 - What if you already have charts made and linked into PowerPoint?
Open the Excel file, open the PPT file, set the zoom back to 100% and update the links. They should work better for you. If some of them don't work correctly, make sure the upper left hand corner of the chart is visible in the Active Window, even if you have to overlay all the charts with a small offset in the upper left hand corner of the worksheet.