diff --git a/libfreerdp/crypto/certificate.c b/libfreerdp/crypto/certificate.c
index 2d64a0508..98090b444 100644
--- a/libfreerdp/crypto/certificate.c
+++ b/libfreerdp/crypto/certificate.c
@@ -300,7 +300,7 @@ BOOL certificate_data_replace(rdpCertificateStore* certificate_store, rdpCertifi
 	char* pline;
 	long int size;
 
-	fp = fopen(certificate_store->file, "wb+");
+	fp = fopen(certificate_store->file, "rb");
 
 	if (!fp)
 		return FALSE;
@@ -330,6 +330,16 @@ BOOL certificate_data_replace(rdpCertificateStore* certificate_store, rdpCertifi
 		return FALSE;
 	}
 
+	fclose(fp);
+
+	fp = fopen(certificate_store->file, "wb+");
+
+	if (!fp)
+	{
+		free(data);
+		return FALSE;
+	}
+
 	/* Write the file back out, with appropriate fingerprint substitutions */
 	data[size] = '\n';
 	data[size + 1] = '\0';