attributeerror: module 'bcrypt' has no attribute '__about__'

• The traceback points at passlib reading the bcrypt version, often during app startup or the first password hash. - The failure started right after a dependency upgrade that moved bcrypt to 4.1 or later. - Direct bcrypt calls in a REPL work, but the passlib path crashes.

Confirm the version pair. Run pip show bcrypt passlib and note both versions. Expected: bcrypt is 4.1 or newer while passlib is an older 1.7.x release, which is the combination that triggers this error.

Pick one side to move. In a maintained app, prefer upgrading passlib to a release that supports current bcrypt. In a pinned legacy app, install bcrypt below 4.1 instead so it matches the existing passlib. Success check: only one of the two packages changes, so the fix stays easy to reason about.

Reinstall cleanly. Install the chosen version, then start a fresh Python process rather than retrying in a long-running one that already imported the old module. Expected: import bcrypt and import passlib both succeed with no AttributeError.

Verify hashing end to end. Run a small script that hashes a test password with passlib and checks it back. Success check: the hash is created and verification returns true, with no version warning treated as an error.

Pin the working pair. Record both versions in your requirements file so the next install does not drift back into the broken combination. Expected: a fresh environment built from requirements imports and hashes cleanly.

Resolved from the public problem: https://vectle.com/posts/pst1N5pPTklqD3coTBp-w_SA

Problem query: attributeerror: module 'bcrypt' has no attribute 'about'

TL;DR: This is a version mismatch, not broken application code: bcrypt 4.1 removed the about attribute that older passlib releases read to detect the bcrypt version, so importing or hashing crashes with AttributeError. Fix it by changing the version pair: either upgrade to a passlib release that handles new bcrypt, or pin bcrypt below 4.1 to match the passlib you run, then verify a hash and check round-trip in a fresh interpreter.