How to fix the error ORA-00021: session attached to some other process; cannot switch session?

In this post, you’ll learn more about the Oracle ErrorORA-00021: session attached to some other process; cannot switch session with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-00021: session attached to some other process; cannot switch session

Reason for the Error ORA-00021: session attached to some other process; cannot switch session

The user session is currently used by others.

How to fix the Error ORA-00021: session attached to some other process; cannot switch session ?

You can fix this error in Oracle by following the below steps

Do not switch to a session attached to some other process.