diff --git a/client/core/servercontroller.cpp b/client/core/servercontroller.cpp
index 0dad3020..ef7a8024 100644
--- a/client/core/servercontroller.cpp
+++ b/client/core/servercontroller.cpp
@@ -664,7 +664,8 @@ ErrorCode ServerController::isServerPortBusy(const ServerCredentials &credential
             ProtocolProps::transportProtoToString(ProtocolProps::defaultTransportProto(protocol), protocol);
     QString transportProto = containerConfig.value(config_key::transport_proto).toString(defaultTransportProto);
 
-    QString script = QString("which lsof &>/dev/null || true && sudo lsof -i -P -n | grep -E ':%1 ").arg(port);
+    // TODO reimplement with netstat
+    QString script = QString("which lsof &>/dev/null || true && sudo lsof -i -P -n 2>/dev/null | grep -E ':%1 ").arg(port);
     for (auto &port : fixedPorts) {
         script = script.append("|:%1").arg(port);
     }
@@ -728,7 +729,7 @@ ErrorCode ServerController::isServerDpkgBusy(const ServerCredentials &credential
 
     QFuture<ErrorCode> future = QtConcurrent::run([this, &stdOut, &cbReadStdOut, &cbReadStdErr, &credentials]() {
         // max 100 attempts
-        for (int i = 0; i < 100; ++i) {
+        for (int i = 0; i < 30; ++i) {
             if (m_cancelInstallation) {
                 return ErrorCode::ServerCancelInstallation;
             }
@@ -738,9 +739,8 @@ ErrorCode ServerController::isServerDpkgBusy(const ServerCredentials &credential
                                   genVarsForScript(credentials)),
                       cbReadStdOut, cbReadStdErr);
 
-            // if 'fuser' is not installed, skip check
-            if (stdOut.contains("Not installed"))
-                return ErrorCode::NoError;
+            if (stdOut.contains("Packet manager not found")) return ErrorCode::ServerPacketManagerError;
+            if (stdOut.contains("fuser not installed")) return ErrorCode::NoError;
 
             if (stdOut.isEmpty()) {
                 return ErrorCode::NoError;
@@ -749,7 +749,7 @@ ErrorCode ServerController::isServerDpkgBusy(const ServerCredentials &credential
                 qDebug().noquote() << stdOut;
 #endif
                 emit serverIsBusy(true);
-                QThread::msleep(5000);
+                QThread::msleep(10000);
             }
         }
         return ErrorCode::ServerPacketManagerError;
diff --git a/client/server_scripts/check_server_is_busy.sh b/client/server_scripts/check_server_is_busy.sh
index 24c2924c..e1ba63f8 100644
--- a/client/server_scripts/check_server_is_busy.sh
+++ b/client/server_scripts/check_server_is_busy.sh
@@ -2,4 +2,4 @@ if which apt-get > /dev/null 2>&1; then LOCK_FILE="/var/lib/dpkg/lock-frontend";
 elif which dnf > /dev/null 2>&1; then LOCK_FILE="/var/run/dnf.pid";\
 elif which yum > /dev/null 2>&1; then LOCK_FILE="/var/run/yum.pid";\
 else echo "Packet manager not found"; echo "Internal error"; exit 1; fi;\
-if command -v fuser > /dev/null 2>&1; then sudo fuser $LOCK_FILE; else  echo "Not installed"; fi
+if command -v fuser > /dev/null 2>&1; then sudo fuser $LOCK_FILE 2>/dev/null; else  echo "fuser not installed"; fi