Try the following: At the lower right corner of your Lab, there should
be a button that shows the progress of the search operation:
Click it. This
will open the Progress view that shows all background tasks.
Select the item "Fetching children of current Search" and click on the
button to
cancel it. Note: This will preserve your search results that
were displayed until now.
If you do not like this solution, you can do a more cautious search next time: specify a number in the Show at once field, e.g. 10 or 50, and iterate manually through the results using the Continue this search button.
Check two things:
See the documentation of the TextGrid Baseline Encoding.