diff --git a/src/lowntfs-3g.c b/src/lowntfs-3g.c
index 6c2f9e65..2252d869 100644
--- a/src/lowntfs-3g.c
+++ b/src/lowntfs-3g.c
@@ -4379,8 +4379,8 @@ int main(int argc, char *argv[])
 		err = NTFS_VOLUME_SYNTAX_ERROR;
 		goto err_out;
 	}
-	if (ntfs_check_if_mounted(opts.device,&existing_mount)
-	    || (existing_mount & NTFS_MF_MOUNTED)) {
+	if (!ntfs_check_if_mounted(opts.device,&existing_mount)
+	    && (existing_mount & NTFS_MF_MOUNTED)) {
 		err = NTFS_VOLUME_LOCKED;
 		goto err_out;
 	}
diff --git a/src/ntfs-3g.c b/src/ntfs-3g.c
index d21f4d53..1aa934f5 100644
--- a/src/ntfs-3g.c
+++ b/src/ntfs-3g.c
@@ -4332,8 +4332,8 @@ int main(int argc, char *argv[])
 		err = NTFS_VOLUME_SYNTAX_ERROR;
 		goto err_out;
 	}
-	if (ntfs_check_if_mounted(opts.device,&existing_mount)
-	    || (existing_mount & NTFS_MF_MOUNTED)) {
+	if (!ntfs_check_if_mounted(opts.device,&existing_mount)
+	    && (existing_mount & NTFS_MF_MOUNTED)) {
 		err = NTFS_VOLUME_LOCKED;
 		goto err_out;
 	}