I had the same problem. It looks like the issue is that bash is missing. Here is how I found it (and some instructions on how to fix it below):
Look in /usr/pbi/crashplan-amd64/share/crashplan/log/service.log.0
I searched for upgrade and then poked around until I found this:
[10.01.15 00:09:31.928 WARN W17006879_DwldMgr com.backup42.common.util.Sys
temUtil ] EXEC:: Exception running command=/bin/bash upgrade.sh, java.io.IOE
xception: Cannot run program "/bin/bash" (in directory "upgrade/1435726800441.14
43683370924"): error=2, No such file or directory, java.io.IOException: Cannot r
un program "/bin/bash" (in directory "upgrade/1435726800441.1443683370924"): err
or=2, No such file or directory
java.io.IOException: Cannot run program "/bin/bash" (in directory "upgrade/14357
26800441.1443683370924"): error=2, No such file or directory
at java.lang.ProcessBuilder.start(Unknown Source)
at com.code42.utils.SystemCommandRunner.start(SystemCommandRunner.java:1
95)
at com.backup42.common.util.SystemUtil.executeCommand(SystemUtil.java:75
)
at com.backup42.common.util.SystemUtil.executeCommand(SystemUtil.java:31
)
at com.backup42.service.upgrade.PatchManager.doPatch(PatchManager.java:2
36)
at com.backup42.service.upgrade.PatchManager.run(PatchManager.java:117)
at com.backup42.service.CPService.filesDownloaded(CPService.java:2632)
at com.backup42.service.upgrade.DownloadManager.doWork(DownloadManager.j
ava:173)
at com.code42.utils.AWorker.run(AWorker.java:149)
at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: error=2, No such file or directory
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(Unknown Source)
at java.lang.ProcessImpl.start(Unknown Source)
... 10 more
Then I looked and noticed that I did not have bash installed. So I installed bash using 'pkg install bash'.
Finally the upgrade still failed, so I ran 'ln -s /usr/local/bin/bash /bin/bash'
Then upgrade succeeded. You can force an upgrade by stopping and starting crashplan with 'service crashplan stop' followed by 'service crashplan start'. There appears to be some kind of throttle on the duration between upgrade attempts. I ran stop and start a few times and then the upgrade succeeded. You can run 'tail -f history.log.0' and watch the progress of the upgrade.