At some point formatting (font and font size) changed for SOME items in SOME columns of my spreadsheet. Oh well. I changed all items manually to their preferred formatting and moved on. When I opened the file next time the changed formatting had returned. ***? This behavior is persistent. With 20,000 records manually fixing this every day isn't going to work.

I'm a beginner and almost certainly inadvertently changed something but I can't figure out what. Does Excel work with templates like Word, could I have a corrupted template? Any suggestions appreciated.

Office 2016
Win10 Pro/PC

Can you post a sample of your file showing the problem?

you can see one cell has a different font and size. this changed at some unknown point for unknown reasons. if corrected, then saved, and the file reopened, the undesired changes will reappear. a quick fix is selecting the column and changing the font properties en masse. unfortunately this removes underlining from just the affected entries that has to be restored manually.

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Please post a copy of your workbook itself, with the code intact.

large file, get it here:
https://www.dropbox.com/s/q45jpr2v22...test.xlsx?dl=0

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Located the line you mentioned in Post #3. It is the same size/font as the others when I run your workbook here.

????

I was thinking perhaps you had some VBA macros working in the background but your workbook does not include any macros. Or formulas that I can find either.

Equally, I cannot see any difference in Font size.

There is conditional formatting for colouring Odd and Even rows but I can't see anything that would cause a problem

If it happens again, rather than manually changing the relevant cells, just select the whole sheet by clicking the triangle to the left of column A and above Row 1, then whilst all is selected, go to Font and re-select the font size

the copy posted was edited since the screenshot. that it opens with the edits intact suggests to me something peculiar to my installation. looking at my copy, I notice that the symptoms seem to be evolving, i.e., some edits are persistent, some are not. I going to reinstall excel first opportunity.