Error on Mac OS 10.14.6
all of sudden all my refs do not show, error is 1561856341. Refs are there, in the web (cloud). On restart the refs show briefly, but then clicking on Sort by Date (or any other heading) shows a blank window in all folders and overall. Not just the folder which was open for Sort by. Updated to Zotero 5.0.33, same problem, error ID 909161895
But while unrelated to this, you're also using an extremely out of date, two-year-old version of Zotero, and I'm unclear why that would be something you would "update" to. You should be running the most recent version, currently 5.0.79.
If you don't see it, you can take a screenshot of what you're seeing, upload it somewhere (e.g., Dropbox), and provide a link here.
But what I do not understand is why this error happened all of a sudden. Did BBT update silently? Did Zotero? I don't think so. All was exactly the same as I had been using for months, intensively. Anyway now on to a new version.
BTW thanks for the quick response and I am a Zotero evangelist with all the graduate students I teach in USA and China.
(wild guess based on username: mijn welgemeende excuses. boetekleed begint na vandaag wat sleets te worden, maar dat is welverdiend)