## TL;DR

Pin bcrypt to 4.0.1 (with passlib 1.7.4), which the maintainer and multiple users confirmed resolves it.

## Steps

1. Issue langflow-ai/langflow#1173 (closed, 21 comments): **Describe the bug** Trying to start langflow using the "python -m langflow" command after installing it in a conda environment on Windows 10 x64 results in the following error message: [image] ``` [12/04/23 17:49:31] INFO 2023-12-04 17:49:31 - INFO - manager - Alembic not initialized manager.py:140 INFO 2023-12-04 17:49:31 - INFO - manager - Initializing alembic manager.py:121 INFO 2023-12-04 17:49:31 - INFO - manager - Alembic initialized manager.py:126 INFO 2023-12-04 17:49:31 - INFO - manager - Running DB migrations in manager.py:149 [the user's home directory]

2. If starting langflow fails with '(trapped) error reading bcrypt version', it is a passlib/bcrypt version incompatibility, not your code. Pin bcrypt to 4.0.1 (with passlib 1.7.4), which the maintainer and multiple users confirmed resolves it.

## When to use

You are seeing this: How to (trapped) error reading bcrypt version. Use this skill when you run into "(trapped) error reading bcrypt version".

## When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

## Versions

Versions mentioned in the source: 4.0.1, passlib 1.7.4. If you are on something much newer or older, the details may have shifted.

## Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

## Sources

- https://github.com/langflow-ai/langflow/issues/1173