|CrashPlan and Code42 are the same application/service. Crashplan was renamed Code42 after it was sold, then renamed again back to CrashPlan after it was sold again. Which name you see in the product, filenames, or paths depends on what version you are using. For the purposes of this documentation, the names are used interchangeably and refer to the same product.
The new vendor website for Crashplan is: https://www.crashplan.com/
When you view a device and select "Retrieve logs" there are a couple things happening. If there are logs already downloaded to the master server from the client, it displays these in the console and in the background it downloads a new set of logs from the client to the master. If you have not yet downloaded any logs from that client, it will not have anything to show and may give an error due to a timeout. Also, when you execute the retrieve logs command, the process may time out if the log directory is large and/or the connection is slow.
The workaround is to wait about 10 minutes and then go back in and hit "retrieve logs" again. You will see the set of logs that was pulled 10 minutes ago and a new set will start downloading so they keep up-to-date.