You can use the Free version of SeekFast for an unlimited period. It has all the functionalities except one limitation - you can search up to 50 files at once.
If you want to search a larger number of files, you can buy the Full version of the program, which can search in up to 1 million files at a time.
Comparison of the features:
|Full program functionalities
|Max number of files per search
|Dedicated support by email