For the third time this week, when I arrived at work today Jenkins had lost all of our build history. (This also happened one other time a couple weeks ago right after I upgraded to 1.558). There are no builds saved on disk on the master machine, and every job shows no builds. When they get launched, they start from the proper number (#700 in one case) - but all existing history is gone.

The logs are confusing. I have two logs from January, and the rest of the logs are filled with the following-

May 14, 2014 2:29:37 AM jenkins.model.lazy.AbstractLazyLoadRunMap search
WARNING: JENKINS-15652 Assertion error #1: failing to load C:\Jenkins\workspace\builds\REUSE_Unit_Tests\CONFIG=ut_intPPCSim, TEST=Aes_UT, label=LOCAL
#350 EXACT: lo=1,hi=0,size=1,size2=1
May 14, 2014 2:29:37 AM jenkins.model.lazy.AbstractLazyLoadRunMap search
WARNING: JENKINS-15652 Assertion error #1: failing to load C:\Jenkins\workspace\builds\REUSE_Unit_Tests\CONFIG=ut_intPPCSim, TEST=Aes_UT, label=LOCAL
#351 DESC: lo=1,hi=0,size=1,size2=1

Those two warnings are just repeated over and over for each job- filling 8 log files in the space of a couple minutes. I have no other clues to go off of, but I need to figure out what is going on here.