I have no problems with open an original .csv file, but when I change the file and save or save as It and re-open it, it will be open corrupt.
I try many thinks, but is doesn’t work.
This problem I have never before with LibreOffice, do I something wrong?
I hope sombody could help me.
The problem is possibly related to the Field Delimiter used in the original file and the delimiter used by LO when you save after changes (unfortunately LO is not smart enough to keep the same delimiter https://bugs.freedesktop.org/show_bug.cgi?id=70111).
What you need to do is open an original file in Notepad, take note of the Field Delimiter used (e.g. Tab) and then in LibreOffice instead of Save do Save As > Text CSV (.csv), check the “Edit filter settings” box and then in the Export Text File dialog, make sure you use the same delimiters as the original file