Error "You can import only CSV files." appears in the Data Import Wizard

This error occurs if the file you are trying to import does not have a ".csv" extension, or if the file name contains a period (".") other than the one for the extension. File name validation has become stricter since the Summer '25 release.

Please correct the file name based on the cause.

Cause 1: The file extension is not ".csv" 

This error occurs if you attempt to directly import a file such as an Excel file (.xls, .xlsx) or a text file (.txt). 

Solution: Please save the file again in CSV (Comma-separated values) (*.csv) format using your application, and then import that file.

Cause 2: The file name contains a period (".") other than for the extension 

Due to a specification change in the Summer '25 release or later, an error may occur if the part of the file name before ".csv" contains a period. 

Solution: Please change the periods in the file name (before the extension) to another character, such as an underscore ("_"). (Example: data.2025.01.csv → data_2025_01.csv)

[Note for Summer '25 and later] 

As a result of this specification change, if a part of the file name separated by a period has five or fewer characters, that part is considered an extension, which will cause an error.

• Allowed example: myFile.something.csv (because "something" has more than five characters)
• Error example: myFile.hi.csv (because "hi" has five or fewer characters and is therefore considered an extension)