Question: I have a file (only one) with some columns with integer numbers. When I change and save file, those columns are automaticaly converted in dates. Does anyone knows how can i prevent this? Thank You!

Answer: 
you might want to check out a similar issue here:

<http://www.mrexcel.com/forum/excel-questions/637277-excel-converting-numbers-dates.html>

(the below suggestions might not be particularly relevant to this issue, but in general, they might help to resolve such a problem)

Selct the cells and go to `Format --> cells --> number` and select Text for the selection 

There's also a one-keystroke solution: type an apostrophe before entering or pasting a pair of numbers that Excel could mistake for a date and month. When you exit the cell, the apostrophe vanishes and the numbers stay numbers, formatted as text.

this is what `microsoft` says:
<http://office.microsoft.com/en-001/excel-help/stop-automatically-changing-numbers-to-dates-HA102809473.aspx>

also if you are pasting data from somewhere else

try `Paste Special`
I just ran into this issue. I am using a webhook to store data to excel on the fly, adding new rows, updating existing data, etc.

I had a special field "step" which is a string who can be "1", "1.1", "1.2", etc. which was treated as date as soon as the value was a "string decimal"...

The only way I could find to fix this issue was to programmatically add a `'` before the value, like `'1.2`.

I tried to apply this to all my fields to avoid excel side effect, but I then noticed that when updating an existing row by merging new values with existing values then the `'` was stripped. So, I end up using a whitelist of fields to escape. I couldn't locate the fields to force adding `'` when merging data due to limitations from the lib I use `google-sheets-node-api`.