diff --git a/src/ADCSensor.cpp b/src/ADCSensor.cpp
index 4aa8cc1..330de52 100644
--- a/src/ADCSensor.cpp
+++ b/src/ADCSensor.cpp
@@ -176,7 +176,7 @@
         (*bridgeGpio).set(0);
     }
     int fd = open(path.c_str(), O_RDONLY);
-    if (fd <= 0)
+    if (fd < 0)
     {
         return; // we're no longer valid
     }
diff --git a/src/CPUSensor.cpp b/src/CPUSensor.cpp
index 1b04299..0ec4bf5 100644
--- a/src/CPUSensor.cpp
+++ b/src/CPUSensor.cpp
@@ -204,7 +204,7 @@
     responseStream.clear();
     inputDev.close();
     int fd = open(path.c_str(), O_RDONLY);
-    if (fd <= 0)
+    if (fd < 0)
     {
         return; // we're no longer valid
     }
diff --git a/src/HwmonTempSensor.cpp b/src/HwmonTempSensor.cpp
index 52ad8fe..d4ed57f 100644
--- a/src/HwmonTempSensor.cpp
+++ b/src/HwmonTempSensor.cpp
@@ -133,7 +133,7 @@
     responseStream.clear();
     inputDev.close();
     int fd = open(path.c_str(), O_RDONLY);
-    if (fd <= 0)
+    if (fd < 0)
     {
         return; // we're no longer valid
     }
diff --git a/src/PSUEvent.cpp b/src/PSUEvent.cpp
index 6d2a3e6..cc7374c 100644
--- a/src/PSUEvent.cpp
+++ b/src/PSUEvent.cpp
@@ -175,7 +175,7 @@
     responseStream.clear();
     inputDev.close();
     int fd = open(path.c_str(), O_RDONLY);
-    if (fd <= 0)
+    if (fd < 0)
     {
         return;
     }
diff --git a/src/PSUSensor.cpp b/src/PSUSensor.cpp
index a7156a7..7c9e109 100644
--- a/src/PSUSensor.cpp
+++ b/src/PSUSensor.cpp
@@ -128,7 +128,7 @@
     responseStream.clear();
     inputDev.close();
     int fd = open(path.c_str(), O_RDONLY);
-    if (fd <= 0)
+    if (fd < 0)
     {
         return;
     }
diff --git a/src/TachSensor.cpp b/src/TachSensor.cpp
index e000780..cca2f23 100644
--- a/src/TachSensor.cpp
+++ b/src/TachSensor.cpp
@@ -179,7 +179,7 @@
     responseStream.clear();
     inputDev.close();
     int fd = open(path.c_str(), O_RDONLY);
-    if (fd <= 0)
+    if (fd < 0)
     {
         return; // we're no longer valid
     }