Mass delete unresolved Tasks

Delete records via the Mass Delete Tool:

Note: You can only delete up to 250 records at a time using this wizard.

1. Navigate to Setup, enter Mass Delete Records in the Quick Find box, then select Mass Delete Records.
2. Click Mass Delete Activities
3. Set up your criteria to include a filter like the following: Subject STARTS WITH "Unresolved Email:" (You can also use other filters to narrow down your search results.)
4. Click Search.
5. You can then select the desired records and click Delete.

Export a report and use Data Loader:

Note: Archived Activities aren't listed in Reports. Use the "Export All" function in Data Loader to export Archived Activities and then perform a Delete.
 

1. Click the Reports tab.
2. Click New Report.
3. Click Activities folder | click Task and Events
4. Click Create.
5. Filter your Data. Make sure that the filter Subject starts with "Unresolved Email:" is included and that the Activity ID is added on your report. 
6. Run Report and click Export Details (in Classic) or click the Export action (in Lightning Experience) and export the report as a CSV.
7. Select the Delete option in Data Loader and map your Activity Id column in the exported CSV to delete the exported records.

See Insert, Update, or Delete Data Using Data Loader for more details.

See Also:

Delete Multiple Records and Reports