It is known that the searches can take exception to a word for no apparent reason and sometimes to do have to try a number of searches using the different engines, different sets of keywords, etc before finding what you are looking for.

This problem does occasionally get reported in the help forum and as far as I understand it, not even Max has managed to explain why it happens. Other than persevering if you are looking for a song that you feel sure must be in the DT, it may be worth downloading the DT Database. I don't know about the Mac version but the PC program which is a DOS program is reported to have a more reliable search facility.

Jon