The “/MCLR” checkbox has the same functionality as the menu selection Programmer>Hold Device in Reset. When the box is checked the target device will be held in Reset. When unchecked, the target circuit is allowed to pull MCLR up to VDD to release the device from Reset.
This function can be used to prevent a device from executing code before and after programming.
Note: If the target device allows the MCLR pin to be configured as an input port,
and it is configured as such, PICkit will not be able to hold the device in
Reset.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Just a quick one then.What are the consequences of ticking/not ticking the MCLR check box in The PicKit3+ programmer
The “/MCLR” checkbox has the same functionality as the menu selection Programmer>Hold Device in Reset. When the box is checked the target device will be held in Reset. When unchecked, the target circuit is allowed to pull MCLR up to VDD to release the device from Reset.
This function can be used to prevent a device from executing code before and after programming.
Note: If the target device allows the MCLR pin to be configured as an input port,
and it is configured as such, PICkit will not be able to hold the device in
Reset.