diff --git a/profiles/cpu-partitioning/tuned.conf b/profiles/cpu-partitioning/tuned.conf
index 303b216..68a571d 100644
--- a/profiles/cpu-partitioning/tuned.conf
+++ b/profiles/cpu-partitioning/tuned.conf
@@ -8,6 +8,10 @@ include=network-latency
 [variables]
 # User is responsible for updating variables.conf with variable content such as isolated_cores=X-Y
 include=/etc/tuned/cpu-partitioning-variables.conf
+
+# Fail if isolated_cores are not set
+assert1=${f:assertion_non_equal:isolated_cores are not set:${isolated_cores}:\\${isolated_cores}}
+
 # tmpdir
 tmpdir=${f:exec:/usr/bin/mktemp:-d}
 # Non-isolated cores cpumask including offline cores
@@ -19,7 +23,7 @@ not_isolated_cores_present_expanded=${f:cpulist_present:${not_isolated_cores_exp
 not_isolated_cpumask=${f:cpulist2hex:${not_isolated_cores_expanded}}
 
 # Fail if isolated_cores contains CPUs which are not present
-assert=${f:assertion:isolated_cores contains present CPU(s):${isolated_cores_expanded}:${isolated_cores_present_expanded}}
+assert2=${f:assertion:isolated_cores contains present CPU(s):${isolated_cores_expanded}:${isolated_cores_present_expanded}}
 
 [sysctl]
 kernel.hung_task_timeout_secs = 600
diff --git a/profiles/realtime-virtual-guest/tuned.conf b/profiles/realtime-virtual-guest/tuned.conf
index 7b36a77..d8e7087 100644
--- a/profiles/realtime-virtual-guest/tuned.conf
+++ b/profiles/realtime-virtual-guest/tuned.conf
@@ -9,11 +9,15 @@ include=realtime
 [variables]
 # User is responsible for adding isolated_cores=X-Y to realtime-virtual-guest-variables.conf
 include=/etc/tuned/realtime-virtual-guest-variables.conf
+
+# Fail if isolated_cores are not set
+assert1=${f:assertion_non_equal:isolated_cores are not set:${isolated_cores}:\\${isolated_cores}}
+
 isolated_cores_expanded=${f:cpulist_unpack:${isolated_cores}}
 isolated_cores_present_expanded=${f:cpulist_present:${isolated_cores}}
 
 # Fail if isolated_cores contains CPUs which are not present
-assert=${f:assertion:isolated_cores contains present CPU(s):${isolated_cores_expanded}:${isolated_cores_present_expanded}}
+assert2=${f:assertion:isolated_cores contains present CPU(s):${isolated_cores_expanded}:${isolated_cores_present_expanded}}
 
 [script]
 script=${i:PROFILE_DIR}/script.sh
diff --git a/profiles/realtime-virtual-host/tuned.conf b/profiles/realtime-virtual-host/tuned.conf
index 8b411c8..b4e5893 100644
--- a/profiles/realtime-virtual-host/tuned.conf
+++ b/profiles/realtime-virtual-host/tuned.conf
@@ -26,11 +26,15 @@ include=realtime
 [variables]
 # User is responsible for adding isolated_cores=X-Y to realtime-virtual-host-variables.conf
 include=/etc/tuned/realtime-virtual-host-variables.conf
+
+# Fail if isolated_cores are not set
+assert1=${f:assertion_non_equal:isolated_cores are not set:${isolated_cores}:\\${isolated_cores}}
+
 isolated_cores_expanded=${f:cpulist_unpack:${isolated_cores}}
 isolated_cores_present_expanded=${f:cpulist_present:${isolated_cores}}
 
 # Fail if isolated_cores contains CPUs which are not present
-assert=${f:assertion:isolated_cores contains present CPU(s):${isolated_cores_expanded}:${isolated_cores_present_expanded}}
+assert2=${f:assertion:isolated_cores contains present CPU(s):${isolated_cores_expanded}:${isolated_cores_present_expanded}}
 
 [scheduler]
 # group.group_name=rule_priority:scheduler_policy:scheduler_priority:core_affinity_in_hex:process_name_regex
diff --git a/profiles/realtime/tuned.conf b/profiles/realtime/tuned.conf
index 2592681..54c3c78 100644
--- a/profiles/realtime/tuned.conf
+++ b/profiles/realtime/tuned.conf
@@ -12,7 +12,7 @@ include = network-latency
 include = /etc/tuned/realtime-variables.conf
 
 # Fail if isolated_cores are not set
-assert1=${f:assertion_non_equal:isolated_cores unset:${isolated_cores}:\${isolated_cores}}
+assert1=${f:assertion_non_equal:isolated_cores are not set:${isolated_cores}:\\${isolated_cores}}
 
 # Non-isolated cores cpumask including offline cores
 not_isolated_cpumask = ${f:cpulist2hex_invert:${isolated_cores}}