Reading the Conversion.log file
You should open and read the Conversion.log file after converting one or multiple files. It lists the conversion status and possible problems found during conversion, such as fields with invalid names.
The log file is created in the same folder as your converted files. If you used the multi-file conversion method to convert more than one file at a time, the Conversion.log file contains information for all the converted files. For more information, search the FileMaker Knowledge Base available at //help.filemaker.com. Also try keywords that appear in any message you see.
In most cases, you can correct problems in converted files. If the log file indicates a problem that would be complicated and time-consuming to fix after conversion, you may want to try correcting the problem in the original file using a previous version of FileMaker Pro, and then convert the file again.
Important  The Conversion.log file may not indicate every item in the file that needs to be corrected. Before you begin using a converted database solution, you should test it thoroughly to make sure every aspect has converted successfully. For example, make sure every script works as you expect, and that accounts and privilege sets provide the required file security.