If you encounter the error (com.apple.StorageKit error 118) when converting JDL to APFS, please refer to the steps below to
reformat it before trying to convert again.
1. Use “Erase” to format the JDL device to the Mac OS Extended format (Journaled format)
and select “GUID Partition Map”, as shown below.
2. Right click the volume and select “Convert to APFS....”
3. Select “Convert”
4. JDL volume changes its location to “external”, as shown below.