This page explains the causes of file corruption and how to resolve them.
For CSV files downloaded from exchanges or custom CSV format files, opening or editing the file may corrupt the file and prevent it from being uploaded.
Download the file from the exchange again and re-upload it directly without opening or editing.
If you want to check or edit the contents of a file before uploading it
Right-click on the downloaded file and select "Open with" -> "Notepad" to open it.
The contents can be viewed and edited in "Notepad".
After editing, the file can be saved without corrupting it by selecting "File" > "Save".
The above is an example for a Windows user.
For non-Windows computers, we are sorry to say that the operating procedures may differ.