diff --git a/cluster/apt.apply.update.sh b/cluster/apt.apply.update.sh
index 5fe0a43..3fceb08 100755
--- a/cluster/apt.apply.update.sh
+++ b/cluster/apt.apply.update.sh
@@ -68,6 +68,23 @@ debug_message() {                                               # {{{
 	return 0
 }
 # }}}
+is_sge_host() {                                                 # {{{
+
+	## Check if SGE commands (qhost) are available
+	if [ "$(command -v qhost)" ]; then
+		return_is_sge_host="0"
+		debug_message "is_sge_host − \
+SGE seems present on this host."
+	else
+		return_is_sge_host="1"
+		debug_message "is_sge_host − \
+SGE is not present on this host."
+	fi
+
+	return "${return_is_sge_host}"
+
+}
+# }}}
 is_apt_upgrade_absent() {                                       # {{{
 
 	## Check if temp APT upgrade file is absent
@@ -211,7 +228,7 @@ procs running (with the pattern: ${RED}${local_proc_pattern}${COLOR_DEBUG}) on t
 
 }
 # }}}
-prepare_host() {                                              # {{{
+prepare_host() {                                                # {{{
 
 	debug_message "prepare_host − \
 Forbid SSH logins,…".
@@ -247,6 +264,11 @@ main() {                                                        # {{{
 
 	manage_args "${ARGS}"
 
+	## If SGE is not yet available on this host
+	### Exit
+	is_sge_host \
+		|| exit 0
+
 	sge_hostname="$(hostname -f)"
 	sge_queues_name="$(qhost -h "${sge_hostname:=/dev/null}" -q -xml \
 		| grep "queue name" \
diff --git a/cluster/apt.check.update.sh b/cluster/apt.check.update.sh
index 415b0e2..fe57509 100755
--- a/cluster/apt.check.update.sh
+++ b/cluster/apt.check.update.sh
@@ -84,6 +84,23 @@ define_vars() {                                                 # {{{
 		| grep --max-count=1 -- "'slots_used'" \
 		| sed 's;.*<queuevalue.*>\(.*\)</queuevalue>;\1;')
 
+}
+# }}}
+is_sge_host() {                                                 # {{{
+
+	## Check if SGE commands (qhost) are available
+	if [ "$(command -v qhost)" ]; then
+		return_is_sge_host="0"
+		debug_message "is_sge_host − \
+SGE seems present on this host."
+	else
+		return_is_sge_host="1"
+		debug_message "is_sge_host − \
+SGE is not present on this host."
+	fi
+
+	return "${return_is_sge_host}"
+
 }
 # }}}
 is_apt_upgrade_absent() {                                       # {{{
@@ -156,6 +173,12 @@ main() {                                                        # {{{
 	## Define all vars
 	define_vars
 
+	## If SGE is not yet available on this host {{{
+	### Exit
+	is_sge_host \
+		|| exit 0
+	## }}}
+
 	## If NO APT package upgrade is available {{{
 	### Ensure to remove any temp file related to APT upgrades
 	### AND Exit
diff --git a/cluster/maco.apply.update.sh b/cluster/maco.apply.update.sh
index 5bebb74..93b9d61 100755
--- a/cluster/maco.apply.update.sh
+++ b/cluster/maco.apply.update.sh
@@ -73,6 +73,23 @@ debug_message() {                                               # {{{
 	return 0
 }
 # }}}
+is_sge_host() {                                                 # {{{
+
+	## Check if SGE commands (qhost) are available
+	if [ "$(command -v qhost)" ]; then
+		return_is_sge_host="0"
+		debug_message "is_sge_host − \
+SGE seems present on this host."
+	else
+		return_is_sge_host="1"
+		debug_message "is_sge_host − \
+SGE is not present on this host."
+	fi
+
+	return "${return_is_sge_host}"
+
+}
+# }}}
 is_apt_upgrade_present() {                                      # {{{
 
 	## Check if temp APT upgrade file exists
@@ -244,6 +261,11 @@ main() {                                                        # {{{
 
 	manage_args "${ARGS}"
 
+	## If SGE is not yet available on this host
+	### Exit
+	is_sge_host \
+		|| exit 0
+
 	sge_hostname="$(hostname -f)"
 	sge_queues_name="$(qhost -h "${sge_hostname:=/dev/null}" -q -xml \
 		| grep "queue name" \
diff --git a/cluster/sge.enable.host.queue.sh b/cluster/sge.enable.host.queue.sh
index f1f4f09..5f4efd2 100755
--- a/cluster/sge.enable.host.queue.sh
+++ b/cluster/sge.enable.host.queue.sh
@@ -147,6 +147,23 @@ ${sge_hostname} is not the current host."
 	sge_queue_flag_pattern="${cluster_dir}/.sge.*.disable"
 }
 # }}}
+is_sge_host() {                                                 # {{{
+
+	## Check if SGE commands (qhost) are available
+	if [ "$(command -v qhost)" ]; then
+		return_is_sge_host="0"
+		debug_message "is_sge_host − \
+SGE seems present on this host."
+	else
+		return_is_sge_host="1"
+		debug_message "is_sge_host − \
+SGE is not present on this host."
+	fi
+
+	return "${return_is_sge_host}"
+
+}
+# }}}
 is_current_host() {                                             # {{{
 
 	local_current_host="${1}"
@@ -427,6 +444,11 @@ main() {                                                        # {{{
 	## Define all vars according the selected options
 	define_vars
 
+	## If SGE is not yet available on this host
+	### Exit
+	is_sge_host \
+		|| exit 0
+
 	## If we need to watch for upgrades
 	if [ "${CHECK_UPGRADE}" -eq "0" ]; then
 		## If APT package upgrade is available