Also, I've found this in the forum and I'm wondering if my issue is similar?
Posts made by kebab69man
RE: Lost History in OperaOpera for Mac
Lost History in OperaOpera for Mac
I used to have History going back to May 2017, but this has now gone.
Opera 57.0.3098.102 MAC OSX
Unfortunately I have no backup and timemachine wasn't setup.
I did use management software, but this was never set to delete Opera's history file and my other browser history: Safari and Firefox are intact.
My last data entry showing in the History list is 18/9/2018, though new history is populating the list.
I have browsed the History file in text editor and there's 6000 .coms when i do a word search, yet theres only a few days entries showing in Opera browser. The file is currently 4.4 meg. I'm sure it should be much bigger hand have 10s of thousands of urls listed?
The only thing I have done is stop using Opera in August because it was having issues playing flash videos on certain sites. I subsequently added an app to export my bookmarks to HTML, then imported them to Firefox.
Last week, I checked my history in Opera to find everything gone prior to the browser change over.