Does Reinstalling Mac OS from Recovery Clears App data? I need to reinstall Mac OS from recovery since Disk Utility was unable to repair some disk errors.

I have few notes in the notes app and important Bookmarks/opened tabs in both Chrome and Firefox, Which I don't want to lose.

Does this kind of data remain after reinstall? or any other way to repair disk errors without losing on this data?
Yes, reinstalling macOS under these circumstances1 may erase app data.

If you don't have a Time Machine backup (and you really really should), then the other options you have are:


export your bookmarks from Firefox as a html file
export your bookmarks from Chrome as a html file
ensure your Notes files are synced to iCloud


You would then just copy the HTML files you exported onto an external USB drive for importing back later, and your Notes files will be available to your other Apple devices (or via the web) assuming you have other Apple devices with iCloud enabled.

Finally, you could also use Chrome's and Firefox's built-in syncing services to save your bookmarks.

NOTE: If you don't use iCloud, you could always just copy and paste your Notes into another app from which you can save them onto an external disk (e.g. TextEdit, Pages, MS Word, etc).

Further reading


Export Firefox bookmarks to an HTML file to back up or transfer bookmarks
Google Chrome Help: Import or export bookmarks
iCloud: Notes overview
Use Time Machine to back up or restore your Mac


1 It's unclear what you mean by 'disk errors', but if these are such that your startup volume needs reformatting then your data will be lost.