For me, it was fixed when I deleted the “Game” Directory inside “./Localization/”. If it exists, Unreal looks for the file and fails when not finding it. With no directory, there is no check.
Actually, this error message is pretty misleading. I read it as “I found this file but I can’t read it”; it should actually say something like “I am looking for this file but I can’t find it”.
The .locmeta file is produced when you perform a text “compile” command; unless you do this step, you probably don’t have this .locmeta file, and the cook will fail until you have it.
To solve, open the Localization Dashboard, select your target (i.e. “Game”), and then click the tiny “Compile” button at the end of the row of buttons next to your native culture (i.e. English). The first time you do this, the output window will display the same error message that the cooker outputs, but when the command finishes you should now see the .locmeta file (as well as a .locres file) in the directory indicated by the same path as the original error message. Your cook should now succeed.