My System: MS Office Excel 2013 on Win7 64bit. I have an excel xlsx-file with different cell formats like General, Currency_USD, Currency_EUR, Number (no decimal places), Number (2 decimal places).
When opening the file at another time, Excel corrupts my number and currency cell formats. Curiously this does not happen directly after saving and opening again. This problem exists at several files.
I recognized, that the cells changes to that format, which I changed one of the last times. And the format is applied to other cells (which I didn't format) after reopening the file some time later.
I.e. if I have some EUR cells, and afterthen I also add some USD cells... when I close and open the file, also the EUR cells are formatted in USD (and also the "number" formatted cells). This also happpens with cells on other sheets. The problem occurs with format "currency" and also with "accounting".
Solving the problem by create custom formats is not a solution - Excel should be able to handle different cell format - also without creating styles for every single format!
In Options/Advanced I already unchecked "Extend data range formats and formulas", but problem still exists.
The question is NOT answered by How to preserve custom number formatting after closing a workbook?: I've tested it and created custom styles and updated the cells, but these cells were overwritten with "normal" style at re-opening!
EDIT 2017-04-11: What I recognized: In most cases the "Normal" style is changed from number format "General" to another format by mistake, after opening the file on another time. Any idea, why this happens?