Problem can arrise if Confluence has the incorrect, or at least inconsistent case sensitivity in the database. Add an operation as part of the startup task that check case sensitivity in the database and compares it with 1) recommend configurations 2) previous startups. Throwing an error message instead of starting up as usual will reduce if not eliminate the problems of Case Inconsistency.

This KB explains well the situation:
https://confluence.atlassian.com/display/CONFKB/Confluence+Does+Not+Start+with+%27MySQL+session+isolation+level+%27REPEATABLE-READ%27+is+no+longer+supported%27+Message
(See screen shot)

The error is clear, however, it doesn't tell what are the next steps.

The page should contain a link to the appropriate section of the MySQL DB settings so that the correct isolation level can be set.