Instruments hangs indefinitely when collecting data

I've been encountering a recurring problem with the Instruments develoloper tools, reproducible on multiple Macs (running Mountain Lion and Mavericks) and with multiple iPhones (running iOS 7). Whenever I try to collect data on all processes for more than ~45 sec, using the Scheduling and/or Time Profiler tools, the program will hang indefinitely, and the data will be irretrievable. The longer I try recording, the lower the likelihood of success. Usually 20 secs is safe, but that is not enough time for my research. More to the point, I know that I am not exceeding my buffer limit (the data output is only on the order of 3-30 MB), and I'm using computers and devices that should easily be able to handle this kind of throughput. To me, this seems like a pretty serious instability in the Instruments software itself, which has made my research all but impractical. Thank you for any suggestions you can offer/attention you can devote to this!