How to modify “Original Estimate” in JIRA after log work in the Issue

To make editable the field “Original Estimate” after log work in the Issue, you must change the “Legacy Mode” in the “Time Tracking” configuration.

About ‘Legacy Mode’

• If Legacy Mode is disabled, your users will be able to change the Original Estimate value irrespective of any work being logged on an issue. Legacy Mode is disabled by default on new installations of JIRA version 4.2 or later.
• If Legacy Mode is enabled, your users can only specify an Original Estimate before they start logging work on an issue. This value cannot be changed once any work has been logged, unless all work logs for that issue are first deleted.
• By default,
  • Legacy Mode is disabled if your JIRA 4.2 installation was conducted cleanly (that is, without upgrading from an earlier version of JIRA).
  • Legacy Mode is enabled if you upgraded JIRA from a version prior to 4.2.