diff --git a/sdk/openbr_plugin.cpp b/sdk/openbr_plugin.cpp
index 20685c3..fb3d3c8 100644
--- a/sdk/openbr_plugin.cpp
+++ b/sdk/openbr_plugin.cpp
@@ -130,10 +130,17 @@ void File::set(const QString &key, const QVariant &value)
 {
     if (key == "Label") {
         bool ok = false;
-        if (value.canConvert(QVariant::Double))
+        const QString valueString = value.toString();
+
+        /* We assume that if the value starts with '0'
+           then it was probably intended to to be a string UID
+           and that it's numerical value is not relevant. */
+        if (value.canConvert(QVariant::Double) &&
+            (!valueString.startsWith('0') || (valueString == "0")))
             value.toFloat(&ok);
-        if (!ok && !Globals->classes.contains(value.toString()))
-            Globals->classes.insert(value.toString(), Globals->classes.size());
+
+        if (!ok && !Globals->classes.contains(valueString))
+            Globals->classes.insert(valueString, Globals->classes.size());
     }
 
     m_metadata.insert(key, value);