How do I re-enable double tap to highlight on my trackpad?

Solution 1:

Here is the answer to your question:

1. Go to System Preferences
2. Select Accessibility
3. Go to Pointer Control in Motor Section
4. Select Mouse & Trackpad
5. Select Trackpad Options
6. Select Enable dragging withoug Drag Lock

Solution 2:

I have searched all locations which come to mind for enabling such a setting, but without success:

• System Preferences → Trackpad
• System Preferences → Accessibility → Keyboard
• System Preferences → Keyboard

Therefore, I suggest the following alternative:
System Preferences→Trackpad→Point & Click→Three Finger Drag

This way you can highlight text without delay by using three finger touch. If you need to highlight lots of text, you can release one of the three fingers and continue to move the cursor down with that finger.

Solution 3:

I was annoyed myself, and found out the answer in the end:

1. System Preferences > Universal Access > Mouse and Trackpad > Trackpad Options
2. Click the check box that says "Dragging" and you should be all set.

For more details see this CNET article.

By the way, the exact method to perform this action has changed slightly with Mountain Lion.