## TL;DR
Connection attempt failed right after a Cisco Secure Client upgrade is usually a stale connection profile, a version mismatch with the headend, or an OS compatibility gap. Re-import a fresh profile, confirm the headend supports the client version, and check the OS release notes.

## The query
```text
cisco secure client "connection attempt failed" after upgrade
```

## Use this when
- Cisco Secure Client broke immediately after upgrading
- one upgraded machine fails while older clients still connect
- profile imports that worked before now fail

## Not for
- login failed with bad credentials (check the password)
- certificate errors (check the machine certificate)
- headend-side outages (check the ASA or FTD)

## Steps
1. Note the exact client version and the OS version, then check Cisco's compatibility notes for that pair. Expected output: a supported combination confirmed or a known bad pair found
2. Delete the existing connection profiles and re-import a fresh profile from your distribution point. Expected output: a clean profile in place
3. Try connecting to the headend hostname directly to rule out profile corruption. Expected output: you know whether the profile was the problem
4. Check with the network team that the headend (ASA/FTD) supports the new client version. Expected output: headend compatibility confirmed
5. If the OS is brand new, check for a Cisco field notice about that OS release. Expected output: any known issue identified
6. Roll back to the previous client version as a workaround while the root cause is fixed. Expected output: user connected on the old version

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_yZ-g13oomrZL43lms7HQPg