diff --git a/tools/pve/pbs4-upgrade.sh b/tools/pve/pbs4-upgrade.sh
index 2a2fa59fd..a05ba8bb9 100644
--- a/tools/pve/pbs4-upgrade.sh
+++ b/tools/pve/pbs4-upgrade.sh
@@ -57,7 +57,9 @@ start_routines() {
   yes)
     msg_info "Switching to Debian 13 (Trixie) Sources"
     rm -f /etc/apt/sources.list.d/*.list
-    sed -i '/proxmox/d;/bookworm/d' /etc/apt/sources.list || true
+    if [ -f /etc/apt/sources.list ]; then
+      sed -i '/proxmox/d;/bookworm/d' /etc/apt/sources.list
+    fi
     cat >/etc/apt/sources.list.d/debian.sources <<EOF
 Types: deb
 URIs: http://deb.debian.org/debian
diff --git a/tools/pve/post-pbs-install.sh b/tools/pve/post-pbs-install.sh
index 80b3cc838..315fa723e 100644
--- a/tools/pve/post-pbs-install.sh
+++ b/tools/pve/post-pbs-install.sh
@@ -188,7 +188,9 @@ start_routines_4() {
   yes)
     msg_info "Correcting Debian Sources (deb822)"
     rm -f /etc/apt/sources.list.d/*.list
-    sed -i '/proxmox/d;/bookworm/d' /etc/apt/sources.list || true
+    if [ -f /etc/apt/sources.list ]; then
+      sed -i '/proxmox/d;/bookworm/d' /etc/apt/sources.list
+    fi
     cat >/etc/apt/sources.list.d/debian.sources <<EOF
 Types: deb
 URIs: http://deb.debian.org/debian/
diff --git a/tools/pve/post-pve-install.sh b/tools/pve/post-pve-install.sh
index 73a702d1f..a2ef030c1 100644
--- a/tools/pve/post-pve-install.sh
+++ b/tools/pve/post-pve-install.sh
@@ -251,8 +251,10 @@ start_routines_9() {
       msg_info "Correcting Proxmox VE Sources (deb822)"
       # remove all existing .list files
       rm -f /etc/apt/sources.list.d/*.list
-      # remove bookworm and proxmox entries from sources.list
-      sed -i '/proxmox/d;/bookworm/d' /etc/apt/sources.list || true
+      # remove bookworm and proxmox entries from sources.list (if it exists)
+      if [ -f /etc/apt/sources.list ]; then
+        sed -i '/proxmox/d;/bookworm/d' /etc/apt/sources.list
+      fi
       # Create new deb822 sources
       cat >/etc/apt/sources.list.d/debian.sources <<EOF
 Types: deb