When I upgraded my Zotero from 1.0.10 to 2.0b5 and MS Word plugin from 1.0b3 to 1.0b4, Zotero functions in my MS Word 2007 document became to work significantly slower. It took ~10 second to finish any task I gave (insert citation, edit citation, refresh, etc...) and Word froze for those ~10 second. Previously with Zotero 1.0.10/Word plugin 1.0b3, with the same Word document, all those tasks took just ~1 second and I barely felt any freeze, so it was very annoying.

My Word document had 96 citations ~12000 words, 223kb, and was written in a compatibility mode (.doc file, but not .docx file). This Word document was converted to fit new version of Zotero when first opened after upgrading Zotero.

I tracked down the source of the problem and discovered that the bibliography generating step was a bottleneck. When I removed the bibliography field in the Word document, Zotero plugin returned to work normally. No delay, no freezing. When I inserted the bibliography back to the document, it became slow again (~10 sec freeze) with every Zotero plugin function. This happened with Zotero 2.0b5 with Word plugin 1.0b4.

Fortunately, I backed up all my Word documents and my Zotero library, so I reverted Zotero back to 1.0.10, and Word plugin back to 1.0.b3. All the functionality in MS Word came back to normal, just like before upgrading. No freeze, very fast.

I suspect a bug in Word plugin 1.0b4 which is not present in 1.0b3, that makes it inefficient in handling a large number of citations. I hope this issue be resolved, so that I can enjoy the enhanced functionality of Zotero 2.0 back again.

Thanks.