diff --git a/modules/backup/acronis-logs.sh b/modules/backup/acronis-logs.sh
index 9ca6348..b542c93 100755
--- a/modules/backup/acronis-logs.sh
+++ b/modules/backup/acronis-logs.sh
@@ -275,7 +275,7 @@ while true; do
             # Check if numeric selection for specific log file
             if [[ "$choice" =~ ^[0-9]+$ ]]; then
                 log_files=($(find "$LOG_DIR" -name "*.log" -type f | sort))
-                if [ $choice -gt 0 ] && [ $choice -le ${#log_files[@]} ]; then
+                if [ "${choice:-0}" -gt 0 ] && [ "${choice:-0}" -le ${#log_files[@]} ]; then
                     selected_log="${log_files[$((choice-1))]}"
                     clear
                     print_banner "Log: $(basename "$selected_log")"
diff --git a/modules/backup/acronis-register.sh b/modules/backup/acronis-register.sh
index 7d56db4..f42689c 100755
--- a/modules/backup/acronis-register.sh
+++ b/modules/backup/acronis-register.sh
@@ -171,7 +171,7 @@ echo -e "${DIM}─────────────────────
 echo ""
 
 # Check result
-if [ $REG_EXIT_CODE -eq 0 ]; then
+if [ "${REG_EXIT_CODE:-0}" -eq 0 ]; then
     print_success "Registration successful!"
     echo ""
 
diff --git a/modules/backup/acronis-uninstall.sh b/modules/backup/acronis-uninstall.sh
index dcd594a..7b64055 100755
--- a/modules/backup/acronis-uninstall.sh
+++ b/modules/backup/acronis-uninstall.sh
@@ -214,7 +214,7 @@ if [ -d "/var/lib/Acronis" ] || [ -d "/usr/lib/Acronis" ]; then
     ((remaining++))
 fi
 
-if [ $remaining -eq 0 ]; then
+if [ "${remaining:-0}" -eq 0 ]; then
     echo "Acronis Cyber Protect has been completely removed from this system."
 else
     echo ""