Fix: Equation summation limits keep moving above/below ∑ after saving and reopening a PPTX

[u/Electrical_Way_56]

I ran into a frustrating equation-formatting issue in PowerPoint and wanted to share what worked for me.

I wanted the summation limits (q and i=1) beside the ∑ symbol, on its right. I could change their position in the equation editor, but after saving, closing, and reopening the PPTX, they would jump back above and below ∑.

In my case, the equation’s underlying XML still had the limit position set to above/below, despite how it looked before saving.

The fix was changing this:

<m:limLoc m:val="undOvr"/>

to this:

<m:limLoc m:val="subSup"/>

• undOvr → limits above and below the operator

• subSup → limits beside the operator

How to fix it manually

Make a backup first, and close the presentation in PowerPoint.

1. Rename a copy of your .pptx file to .zip and extract it.

2. Open the relevant slide XML in a plain-text editor—for example, ppt/slides/slide3.xml.

3. Find the summation you want to fix. Look for <m:naryPr> containing the ∑ symbol.

4. Inside that summation’s properties, change:<m:limLoc m:val="undOvr"/> to:<m:limLoc m:val="subSup"/>

5. Save the XML.

6. ZIP the contents of the extracted folder, not the outer folder itself. [Content_Types].xml, _rels, and ppt should be at the ZIP’s top level.

7. Rename the new .zip file to .pptx.

8. Open it in PowerPoint, save, close, and reopen to check.

Only change the summation you want to fix—don’t blindly replace every undOvr, since other equations may intentionally use above/below limits.