So when you say "I cannot open zotero standalone" you mean you can't get it to connect to Chrome, correct?
If so, with Chrome open, what happens when you put
http://127.0.0.1:23119/connector/ping in the address bar and press return
(It should say "Endpoint is not supported by this application" )
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If so, with Chrome open, what happens when you put
http://127.0.0.1:23119/connector/ping in the address bar and press return
(It should say "Endpoint is not supported by this application" )