S.M.A.R.T. Extended Test Failed Error Code:7

I ran the test on an internal HD from WD Dashboard. Results showed this message. What does error code 7 mean? Dashboard status showed normal health for the HD. An Acronis backup failed on one partition, showing block errors. I ran chkdsk /f /r on the partition several times, but the Acronis backup still failed.

As always the preferred search engine might find an answer:

https://en.wikipedia.org/wiki/S.M.A.R.T.

@cbanks

SMART (Self-Monitoring Analysis And Reporting Technology) Definition (techterms.com)

error 7 - how to fix error (wikifixes.com)

This is what the Wiki page showed:
Rate of seek errors of the magnetic heads. If there is a partial failure in the mechanical positioning system, then seek errors will arise. Such a failure may be due to numerous factors, such as damage to a servo, or thermal widening of the hard disk. The raw value has different structure for different vendors and is often not meaningful as a decimal number. For some drives, this number may increase during normal operation without necessarily signifying errors.

How can I determine whether the error is significant for my HD?

I ran the repair utility suggested in the wikifixes article. Dashboad still fails the extended test with error code 7. The short test still shows a normal result.

If the disk is under some warranty, ask the producer or require replacement under warranty.
Otherwise replace disk on your own costs or live with that error and its included risks.

I could replace the long out of warranty drive, but I would like to complete the Acronis backup so I can restore to any new drive.

This option does not exist. Even if a try to backup some data on that disk finally succeeds, that backup might not be readable on a try to use it for restoring its source.
In addition one might like to follow the rule to have at least two recent backups nearly all the time.