Error while updating debug log trace flag

Some times we will receive below error while setting  debug log trace flag for user

"Having an active trace flag triggers debug logging. You have 259 MB of the maximum 250 MB of debug logs. Before you can edit trace flags, delete some debug logs."

Solution:

• In dev console, Select tab "Query Editor" at the bottom of the console
• Select check box "Use Tooling API"
• Use this query: SELECT Id FROM ApexLog
• Delete all rows

Once all rows are deleted you will be able to save new debug logs.