188BET靠谱吗After reinstalling or downgrading Zotero, you may see the following error message when you you try to open Zotero:

188BET靠谱吗This version of Zotero is older than the version last used with your database.188BET靠谱吗Please upgrade to the latest version from zotero.org.

188BET靠谱吗This message results from trying to use a Zotero database from a later version of Zotero in an earlier version of the software.188BET靠谱吗For example, if you installed Zotero 5.0 but then reinstalled Zotero 4.0.29.15, you would get this error.188BET靠谱吗Most Zotero versions preserve backward database compatibility, but occasionally it's necessary for Zotero developers to make changes to the database that prevent it from working with previous versions.

188BET靠谱吗The best solution is generally to reinstall the latest version of Zotero from188BET靠谱吗zotero.org.188BET靠谱吗(If you were using the Zotero Beta, you may need to reinstall thelatest beta build.)

188BET靠谱吗If for some reason you don't want to or are not able to install the latest version, you can restore the pre-upgrade database backup that Zotero stored in your188BET靠谱吗Zotero data directory.188BET靠谱吗Look for the zotero.sqlite.*.bak file with the highest number (e.g., zotero.sqlite.77.bak).188BET靠谱吗Close Zotero, move your existing zotero.sqlite file out of the way, and then copy the numbered backup file into place as zotero.sqlite.188BET靠谱吗Then restart Zotero.

188BET靠谱吗If you don't have data you care about, or if you've fully synced your data and files with your online account, you can keep your current Zotero version by closing Zotero/Firefox, deleting your188BET靠谱吗Zotero data directorycompletely, and, optionally, syncing to restore your previous data.

Previously, the most common cause of this error was having used Juris-M (formerly known as MLZ).The current version of that software no longer causes this.Seethis post188BET靠谱吗by Juris-M's developer on how to securely return to using regular Zotero.