mobi-asin - edit identifier question

[clady]

When adding books to calibre, sometimes and much more recently...the amazon identifier shows as mobi-asin instead of amazon. When downloading the metadata for those books, I usually get a msg that says that the book's metadata can not be found. I have to change the mobi-asin to amazon to get the metadata search to work properly. I might have a setting set to the improper setting that is causing the problem. It used to d/l the metadata correctly whether it said mobi-asin: or amazon: but not for awhile.

Is there a plugin or some steps that would make it easier to rename all the mobi-asin to amazon? I could not find a way to rename all the mobi-asin identifiers to amazon.

Thanks for any hints or helps that anyone might have.