SpamSieve could not find the favorite mailbox "Spam"

I get below message although “Spam” is in my favorites bar.

https://www.evernote.com/shard/s4/sh/f574b0f5-d2e6-4874-be4b-04ab52f319bc/00b93c0a6b58cad19cae87c2a1877961

Mac OSX 10.9.1
SpamSieve 2.9.12

In SpamSieve 2.9.12, the AppleMailTrainSpamGUIScripting esoteric preference only works when Mail is running in English. Please contact me via e-mail to get a beta version of SpamSieve that removes this limitation.

Having same problem.

I am running in English. Spamsieve 2.9.12 & OSX 10.9.1

Note, the command is working, so the message appears to be erroneous (if that helps with debug).

Please also make sure that the Spam mailbox is among the first 9 items in Mail’s Favorites bar.

It’s not erroneous. If it can’t find the button on the Favorites bar, it uses the slower, non-GUI scripting method as a fallback.

This is addressed in SpamSieve 2.9.13.