diff --git a/gamemodes/zombiesurvival/entities/entities/point_propnocollide.lua b/gamemodes/zombiesurvival/entities/entities/point_propnocollide.lua
index f76dc29..9f312de 100644
--- a/gamemodes/zombiesurvival/entities/entities/point_propnocollide.lua
+++ b/gamemodes/zombiesurvival/entities/entities/point_propnocollide.lua
@@ -23,7 +23,7 @@ function ENT:SetProp(ent)
 	local teamid = self:GetTeam()
 	local inrad = false
 	for _, pl in pairs(ents.FindInSphere(ent:LocalToWorld(ent:OBBCenter()), ent:BoundingRadius() / 2 + self:GetExtraRadius())) do
-		if pl:IsValid() and pl:IsPlayer() and pl:Alive() and (teamid == 0 or pl:Team() == teamid) then
+		if pl and pl:IsValid() and pl:IsPlayer() and pl:Alive() and (teamid == 0 or pl:Team() == teamid) then
 			inrad = true
 			break
 		end
@@ -65,7 +65,7 @@ function ENT:Think()
 	local center = ent:LocalToWorld(ent:OBBCenter())
 
 	for _, pl in pairs(ents.FindInSphere(center, ent:BoundingRadius() / 2 + self:GetExtraRadius())) do
-		if pl:IsValid() and pl:IsPlayer() and pl:Alive() and (teamid == 0 or pl:Team() == teamid) then
+		if pl and pl:IsValid() and pl:IsPlayer() and pl:Alive() and (teamid == 0 or pl:Team() == teamid) then
 			pushout = true
 
 			if timeout then
diff --git a/gamemodes/zombiesurvival/entities/entities/status_ghost_arsenalcrate/shared.lua b/gamemodes/zombiesurvival/entities/entities/status_ghost_arsenalcrate/shared.lua
index 3662a60..e13ce1d 100644
--- a/gamemodes/zombiesurvival/entities/entities/status_ghost_arsenalcrate/shared.lua
+++ b/gamemodes/zombiesurvival/entities/entities/status_ghost_arsenalcrate/shared.lua
@@ -13,7 +13,7 @@ end
 
 function ENT:IsInsideProp()
 	for _, ent in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-		if ent ~= self and ent:IsValid() and ent:GetMoveType() == MOVETYPE_VPHYSICS and ent:GetSolid() > 0 then return true end
+		if ent and ent ~= self and ent:IsValid() and ent:GetMoveType() == MOVETYPE_VPHYSICS and ent:GetSolid() > 0 then return true end
 	end
 
 	return false
@@ -41,7 +41,7 @@ function ENT:RecalculateValidity()
 			valid = false
 		else
 			for _, ent in pairs(ents.FindInSphere(tr.HitPos, 128)) do
-				if ent:IsValid() and ent:GetClass() == "prop_arsenalcrate" then
+				if ent and ent:IsValid() and ent:GetClass() == "prop_arsenalcrate" then
 					valid = false
 					break
 				end
diff --git a/gamemodes/zombiesurvival/entities/entities/status_ghost_base/shared.lua b/gamemodes/zombiesurvival/entities/entities/status_ghost_base/shared.lua
index 3d2c7ef..3ed5b66 100644
--- a/gamemodes/zombiesurvival/entities/entities/status_ghost_base/shared.lua
+++ b/gamemodes/zombiesurvival/entities/entities/status_ghost_base/shared.lua
@@ -19,7 +19,7 @@ end
 
 function ENT:IsInsideProp()
 	for _, ent in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-		if ent ~= self and ent:IsValid() and ent:GetMoveType() == MOVETYPE_VPHYSICS and ent:GetSolid() > 0 then return true end
+		if ent and ent ~= self and ent:IsValid() and ent:GetMoveType() == MOVETYPE_VPHYSICS and ent:GetSolid() > 0 then return true end
 	end
 
 	return false
@@ -56,7 +56,7 @@ function ENT:RecalculateValidity()
 			valid = false
 		elseif self.GhostDistance then
 			for _, ent in pairs(ents.FindInSphere(tr.HitPos, self.GhostDistance)) do
-				if ent:IsValid() and ent:GetClass() == self.GhostEntity then
+				if ent and ent:IsValid() and ent:GetClass() == self.GhostEntity then
 					valid = false
 					break
 				end
diff --git a/gamemodes/zombiesurvival/entities/entities/status_ghost_messagebeacon/shared.lua b/gamemodes/zombiesurvival/entities/entities/status_ghost_messagebeacon/shared.lua
index d1d81da..f086c41 100644
--- a/gamemodes/zombiesurvival/entities/entities/status_ghost_messagebeacon/shared.lua
+++ b/gamemodes/zombiesurvival/entities/entities/status_ghost_messagebeacon/shared.lua
@@ -14,7 +14,7 @@ end
 
 function ENT:IsInsideProp()
 	for _, ent in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-		if ent ~= self and ent:IsValid() and ent:GetMoveType() == MOVETYPE_VPHYSICS and ent:GetSolid() > 0 then return true end
+		if ent and ent ~= self and ent:IsValid() and ent:GetMoveType() == MOVETYPE_VPHYSICS and ent:GetSolid() > 0 then return true end
 	end
 
 	return false
@@ -37,7 +37,7 @@ function ENT:RecalculateValidity()
 			valid = false
 		else
 			for _, ent in pairs(ents.FindInSphere(tr.HitPos, 48)) do
-				if ent:IsValid() and ent:GetClass() == "prop_messagebeacon" then
+				if ent and ent:IsValid() and ent:GetClass() == "prop_messagebeacon" then
 					valid = false
 					break
 				end
diff --git a/gamemodes/zombiesurvival/entities/entities/zombiegasses/init.lua b/gamemodes/zombiesurvival/entities/entities/zombiegasses/init.lua
index 6ba654b..2b95195 100644
--- a/gamemodes/zombiesurvival/entities/entities/zombiegasses/init.lua
+++ b/gamemodes/zombiesurvival/entities/entities/zombiegasses/init.lua
@@ -37,7 +37,7 @@ function ENT:AcceptInput(name, activator, caller, arg)
 
 	local vPos = self:GetPos()
 	for _, ent in pairs(ents.FindInSphere(vPos, self:GetRadius())) do
-		if ent:IsPlayer() and ent:Alive() and WorldVisible(vPos, ent:NearestPoint(vPos)) then
+		if ent and ent:IsValid() and ent:IsPlayer() and ent:Alive() and WorldVisible(vPos, ent:NearestPoint(vPos)) then
 			if ent:Team() == TEAM_UNDEAD then
 				--[[if ent:Health() < ent:GetMaxHealth() and not ent:GetZombieClassTable().Boss then
 					ent:SetHealth(math.min(ent:GetMaxZombieHealth(), ent:Health() + self.Heal))
diff --git a/gamemodes/zombiesurvival/entities/weapons/weapon_zs_chemzombie/init.lua b/gamemodes/zombiesurvival/entities/weapons/weapon_zs_chemzombie/init.lua
index 61d9473..1598043 100644
--- a/gamemodes/zombiesurvival/entities/weapons/weapon_zs_chemzombie/init.lua
+++ b/gamemodes/zombiesurvival/entities/weapons/weapon_zs_chemzombie/init.lua
@@ -15,7 +15,7 @@ function SWEP:Think()
 
 		local origin = self.Owner:LocalToWorld(self.Owner:OBBCenter())
 		for _, ent in pairs(ents.FindInSphere(origin, 40)) do
-			if ent:IsPlayer() and ent:Team() ~= TEAM_UNDEAD and ent:Alive() and TrueVisible(origin, ent:NearestPoint(origin)) then
+			if ent and ent:IsValid() and ent:IsPlayer() and ent:Team() ~= TEAM_UNDEAD and ent:Alive() and TrueVisible(origin, ent:NearestPoint(origin)) then
 				ent:PoisonDamage(1, self.Owner, self)
 			end
 		end
diff --git a/gamemodes/zombiesurvival/entities/weapons/weapon_zs_wraith/shared.lua b/gamemodes/zombiesurvival/entities/weapons/weapon_zs_wraith/shared.lua
index 9966547..80eea2e 100644
--- a/gamemodes/zombiesurvival/entities/weapons/weapon_zs_wraith/shared.lua
+++ b/gamemodes/zombiesurvival/entities/weapons/weapon_zs_wraith/shared.lua
@@ -93,7 +93,7 @@ function SWEP:DoAlert()
 	local mouthpos = owner:EyePos() + owner:GetUp() * -3
 	local screampos = mouthpos + owner:GetAimVector() * 16
 	for _, ent in pairs(ents.FindInSphere(screampos, 92)) do
-		if ent:IsPlayer() and ent:Team() ~= owner:Team() then
+		if ent and ent:IsValid() and ent:IsPlayer() and ent:Team() ~= owner:Team() then
 			local entearpos = ent:EyePos()
 			local dist = screampos:Distance(entearpos)
 			if dist <= 92 and TrueVisible(entearpos, screampos) then
diff --git a/gamemodes/zombiesurvival/gamemode/init.lua b/gamemodes/zombiesurvival/gamemode/init.lua
index 86d7a95..2d3d0a4 100644
--- a/gamemodes/zombiesurvival/gamemode/init.lua
+++ b/gamemodes/zombiesurvival/gamemode/init.lua
@@ -787,7 +787,7 @@ function GM:PlayerSelectSpawn(pl)
 				local blocked
 				local spawnpos = spawn:GetPos()
 				for _, ent in pairs(ents.FindInBox(spawnpos + playermins, spawnpos + playermaxs)) do
-					if ent:IsPlayer() and not spawninplayer or string.sub(ent:GetClass(), 1, 5) == "prop_" then
+					if ent and ent:IsValid() and ent:IsPlayer() and not spawninplayer or string.sub(ent:GetClass(), 1, 5) == "prop_" then
 						blocked = true
 						break
 					end
@@ -1737,7 +1737,7 @@ end
 function GM:EvaluatePropFreeze(ent, neighbors)
 	if not ent then
 		for _, e in pairs(ents.GetAll()) do
-			if e:IsValid() then
+			if e and e:IsValid() then
 				self:EvaluatePropFreeze(e)
 			end
 		end
diff --git a/gamemodes/zombiesurvival/gamemode/obj_entity_extend.lua b/gamemodes/zombiesurvival/gamemode/obj_entity_extend.lua
index 479cc94..c0df48c 100644
--- a/gamemodes/zombiesurvival/gamemode/obj_entity_extend.lua
+++ b/gamemodes/zombiesurvival/gamemode/obj_entity_extend.lua
@@ -153,7 +153,7 @@ end
 local function barricadetimer(self, timername)
 	if self:IsValid() then
 		for _, e in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-			if e:IsPlayer() and e:Alive() then
+			if e and e:IsValid() and e:IsPlayer() and e:Alive() then
 				return
 			end
 		end
@@ -169,7 +169,7 @@ function meta:TemporaryBarricadeObject()
 	if self.IsBarricadeObject then return end
 
 	for _, e in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-		if e:IsPlayer() and e:Alive() then
+		if e and e:IsValid() and e:IsPlayer() and e:Alive() then
 			self.IsBarricadeObject = true
 			self:CollisionRulesChanged()
 
diff --git a/gamemodes/zombiesurvival/gamemode/obj_entity_extend_sv.lua b/gamemodes/zombiesurvival/gamemode/obj_entity_extend_sv.lua
index c60bae5..f2b3c98 100644
--- a/gamemodes/zombiesurvival/gamemode/obj_entity_extend_sv.lua
+++ b/gamemodes/zombiesurvival/gamemode/obj_entity_extend_sv.lua
@@ -367,7 +367,7 @@ end
 
 local function GetNailOwner(nail, filter)
 	for _, ent in pairs(ents.GetAll()) do
-		if ent ~= filter and ent.Nails then
+		if ent and ent ~= filter and ent.Nails and ent:isValid() then
 			for __, n in pairs(ent.Nails) do
 				if n == nail then
 					return ent
diff --git a/gamemodes/zombiesurvival/gamemode/obj_player_extend.lua b/gamemodes/zombiesurvival/gamemode/obj_player_extend.lua
index cf54f90..215778f 100644
--- a/gamemodes/zombiesurvival/gamemode/obj_player_extend.lua
+++ b/gamemodes/zombiesurvival/gamemode/obj_player_extend.lua
@@ -444,7 +444,7 @@ end
 local function nocollidetimer(self, timername)
 	if self:IsValid() then
 		for _, e in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-			if e:IsPlayer() and e ~= self and GAMEMODE:ShouldCollide(self, e) then
+			if e and e:IsValid() and e:IsPlayer() and e ~= self and GAMEMODE:ShouldCollide(self, e) then
 				return
 			end
 		end
@@ -459,7 +459,7 @@ function meta:TemporaryNoCollide(force)
 	if self:GetCollisionGroup() ~= COLLISION_GROUP_PLAYER and not force then return end
 
 	for _, e in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-		if e:IsPlayer() and e ~= self and GAMEMODE:ShouldCollide(self, e) then
+		if e and e:IsValid() and e:IsPlayer() and e ~= self and GAMEMODE:ShouldCollide(self, e) then
 			self:SetCollisionGroup(COLLISION_GROUP_DEBRIS_TRIGGER)
 
 			local timername = "TemporaryNoCollide"..self:UniqueID()
@@ -547,7 +547,7 @@ function meta:ActiveBarricadeGhosting(override)
 	if self:Team() ~= TEAM_HUMAN and not override or not self:GetBarricadeGhosting() then return false end
 
 	for _, ent in pairs(ents.FindInBox(self:WorldSpaceAABB())) do
-		if self:ShouldBarricadeGhostWith(ent) then return true end
+		if ent and ent:IsValid() and self:ShouldBarricadeGhostWith(ent) then return true end
 	end
 
 	return false
diff --git a/gamemodes/zombiesurvival/gamemode/sh_crafts.lua b/gamemodes/zombiesurvival/gamemode/sh_crafts.lua
index be69d6b..fb4c016 100644
--- a/gamemodes/zombiesurvival/gamemode/sh_crafts.lua
+++ b/gamemodes/zombiesurvival/gamemode/sh_crafts.lua
@@ -182,7 +182,7 @@ function GM:CanCraft(pl, craft)
 	if not pl:IsValid() or not pl:Alive() or pl:Team() ~= TEAM_HUMAN then return false end
 
 	local plpos = pl:EyePos()
-	local entities = ents.FindInSphere(plpos, self.CraftingRange)
+	local entities = ents.FindValidInSphere(plpos, self.CraftingRange)
 
 	if craft.CanCraft and not craft:CanCraft(pl, entities, plpos) then return false end
 
diff --git a/gamemodes/zombiesurvival/gamemode/sh_util.lua b/gamemodes/zombiesurvival/gamemode/sh_util.lua
index cd5a27c..d64f9aa 100644
--- a/gamemodes/zombiesurvival/gamemode/sh_util.lua
+++ b/gamemodes/zombiesurvival/gamemode/sh_util.lua
@@ -118,9 +118,11 @@ end
 function util.BlastDamageEx(inflictor, attacker, epicenter, radius, damage, damagetype)
 	local filter = inflictor
 	for _, ent in pairs(ents.FindInSphere(epicenter, radius)) do
-		local nearest = ent:NearestPoint(epicenter)
-		if TrueVisibleFilters(epicenter, nearest, inflictor, ent) then
-			ent:TakeSpecialDamage(((radius - nearest:Distance(epicenter)) / radius) * damage, damagetype, attacker, inflictor, nearest)
+		if ent and ent:IsValid() then
+			local nearest = ent:NearestPoint(epicenter)
+			if TrueVisibleFilters(epicenter, nearest, inflictor, ent) then
+				ent:TakeSpecialDamage(((radius - nearest:Distance(epicenter)) / radius) * damage, damagetype, attacker, inflictor, nearest)
+			end
 		end
 	end
 end
@@ -129,12 +131,26 @@ function util.BlastDamage2(inflictor, attacker, epicenter, radius, damage)
 	util.BlastDamageEx(inflictor, attacker, epicenter, radius, damage, DMG_BLAST)
 end
 
+function util.FindValidInSphere(pos, radius)
+	local ret = {}
+	
+	for _, ent in pairs(util.FindInSphere(pos, radius)) do
+		if ent and ent:IsValid() then
+			ret[#ret + 1] = ent
+		end
+	end
+
+	return ret
+end
+
 function util.PoisonBlastDamage(inflictor, attacker, epicenter, radius, damage, noreduce)
 	local filter = inflictor
 	for _, ent in pairs(ents.FindInSphere(epicenter, radius)) do
-		local nearest = ent:NearestPoint(epicenter)
-		if TrueVisibleFilters(epicenter, nearest, inflictor, ent) then
-			ent:PoisonDamage(((radius - nearest:Distance(epicenter)) / radius) * damage, attacker, inflictor, nil, noreduce)
+		if ent and ent:IsValid() then
+			local nearest = ent:NearestPoint(epicenter)
+			if TrueVisibleFilters(epicenter, nearest, inflictor, ent) then
+				ent:PoisonDamage(((radius - nearest:Distance(epicenter)) / radius) * damage, attacker, inflictor, nil, noreduce)
+			end
 		end
 	end
 end
diff --git a/gamemodes/zombiesurvival/gamemode/sv_profiling.lua b/gamemodes/zombiesurvival/gamemode/sv_profiling.lua
index 0b41f83..af15a61 100644
--- a/gamemodes/zombiesurvival/gamemode/sv_profiling.lua
+++ b/gamemodes/zombiesurvival/gamemode/sv_profiling.lua
@@ -128,10 +128,12 @@ function GM:ProfilerPlayerValid(pl)
 
 	-- Are they near a trigger hurt?
 	for _, ent in pairs(ents.FindInSphere(plcenter, 256)) do
-		local entclass = ent:GetClass()
-		if entclass == "trigger_hurt" then
-			--print('trigger hurt')
-			return false
+		if ent and ent:IsValid() then
+			local entclass = ent:GetClass()
+			if entclass == "trigger_hurt" then
+				--print('trigger hurt')
+				return false
+			end
 		end
 	end
 
diff --git a/gamemodes/zombiesurvival/gamemode/sv_zombieescape.lua b/gamemodes/zombiesurvival/gamemode/sv_zombieescape.lua
index a7d5729..a1fb633 100644
--- a/gamemodes/zombiesurvival/gamemode/sv_zombieescape.lua
+++ b/gamemodes/zombiesurvival/gamemode/sv_zombieescape.lua
@@ -37,7 +37,7 @@ hook.Add("InitPostEntityMap", "zombieescape", function(fromze)
 	end
 
 	for _, ent in pairs(ents.GetAll()) do
-		if ent.ZEDelete then
+		if ent and ent.ZEDelete and ent:IsValid() then
 			ent:Remove()
 		end
 	end