Reference > Converting files from FileMaker Pro 11 and earlier > Converting multiple files at once
Converting multiple files at once
Use the multiple-file conversion method to convert all the files in a relational database. See Converting multiple files at once.
FileMaker Pro 15 can convert multiple files at the same time. You should use the multifile conversion method when you need to convert a database composed of multiple related files, or you simply have many FileMaker Pro files that you want to quickly convert without being prompted to individually rename each file.
Note  If a filename includes a period (.), other than the one that precedes the filename extension, remove it. If a period exists in a filename, FileMaker Pro won’t add the .fmp12 extension to the converted file.
To convert multiple files at once:
1. If the files you want to convert are currently open in the previous version of FileMaker Pro, close the files.
2. Create a new, empty folder for the converted files.
3. Do one of the following to select and open the files you want to convert:
Files method: Select the files you want to convert, then drag them to the FileMaker Pro 15 application icon.
Folder method: If a folder contains all of the files you want to convert, drag the folder to the FileMaker Pro 15 application icon.
When multiple files from separate folders are converted, all converted files are created in the same folder. The original files’ locations are not preserved. To make converting files easier, convert all the files from a multifile relational database at the same time. After the conversion, you can move either set of files into a duplicate of your original file structure.
Open dialog box method: In FileMaker Pro 15, choose File menu > Open. In the My Solutions tab in the Launch Center window, click Browse, then select the files you want to convert by holding down Ctrl (Windows) or Command (OS X) and clicking each file. (You can also select a range of adjacent files by clicking the first file and then Shift-clicking the last file in the range.) Then click Open.
The Open Multiple Files dialog box appears.
4. Choose Open all files and convert when necessary.
5. Click Specify, choose the folder you created in step 2 where you want to save the converted files, and click OK (Windows) or Choose (OS X).
Important  Do not choose a folder that contains any of your original files. If you do, the converted files may be renamed (by appending a number to the filename) to prevent the converted files from replacing the original files. This renaming of files could cause data sources (formerly known as file references) to convert improperly, which affects relationships and other features that rely on data sources.
6. Click Open in the Open Multiple files dialog box to start the conversion.
During a prolonged conversion, the File Format Conversion dialog box will appear and show the conversion progress. If a file being converted contains indexed fields, you can save time by clicking Skip when the index is being re-created, which postpones indexing until later.
FileMaker Pro 15 creates converted files in the folder you specified and opens them, leaving your original files unchanged. The filename extension .fmp12 is added to all converted files.
7. Using a text editor, open the Conversion.log file located in the folder that contains your converted database files.