Some essentials userdata deleted suddently

Hello,

I run a craftbukkit 1.7.9-r0.1 server and I'm hurted to a big problem : some essentials userdata are suddently deleted (0 bites files) and their money is setted back to 0 dollars. What is the cause of the problem ?

Here is my plugins :
[22:28:13] [Server thread/INFO]: Plugins (37): GroupManager, Giants, WorldEdit, CCLogger, MaxBans, Vault, Multiverse-Core, PlayerHeads, ColorMatch, NoobResponse, WorldGuard, AntiJoinBot, AutoMessage, TNTRun, KingKits, CoreProtect, BowSpleef, OpenInv, BedwarsRel, Lockette, ProtocolLib, PluginTweaks, AreaShop, Essentials, Jobs, EssentialsProtect, EssentialsSpawn, Multiverse-Portals, Multiverse-Inventories, HeavySpleef, Multiverse-NetherPortals, JSONAPI, ChestShop, EssentialsChat, BattleArena, ArenaCTF, AuthMe

 

Is your server in offline mode?