diff --git a/lib/connect.c b/lib/connect.c
index 91d68e216..b8fde5580 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -1092,9 +1092,11 @@ static void nosigpipe(struct Curl_easy *data,
   int onoff = 1;
   if(setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, (void *)&onoff,
                 sizeof(onoff)) < 0) {
+#if !defined(CURL_DISABLE_VERBOSE_STRINGS)
     char buffer[STRERROR_LEN];
     infof(data, "Could not set SO_NOSIGPIPE: %s",
           Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
+#endif
   }
 }
 #else
diff --git a/lib/vauth/digest_sspi.c b/lib/vauth/digest_sspi.c
index 53c4df08a..94f8f8c0d 100644
--- a/lib/vauth/digest_sspi.c
+++ b/lib/vauth/digest_sspi.c
@@ -197,7 +197,9 @@ CURLcode Curl_auth_create_digest_md5_message(struct Curl_easy *data,
      status == SEC_I_COMPLETE_AND_CONTINUE)
     s_pSecFn->CompleteAuthToken(&credentials, &resp_desc);
   else if(status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED) {
+#if !defined(CURL_DISABLE_VERBOSE_STRINGS)
     char buffer[STRERROR_LEN];
+#endif
 
     s_pSecFn->FreeCredentialsHandle(&credentials);
     Curl_sspi_free_identity(p_identity);
@@ -585,7 +587,9 @@ CURLcode Curl_auth_create_digest_http_message(struct Curl_easy *data,
        status == SEC_I_COMPLETE_AND_CONTINUE)
       s_pSecFn->CompleteAuthToken(&credentials, &resp_desc);
     else if(status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED) {
+#if !defined(CURL_DISABLE_VERBOSE_STRINGS)
       char buffer[STRERROR_LEN];
+#endif
 
       s_pSecFn->FreeCredentialsHandle(&credentials);
 
diff --git a/lib/vauth/krb5_sspi.c b/lib/vauth/krb5_sspi.c
index 6899570f8..8f7a2b02d 100644
--- a/lib/vauth/krb5_sspi.c
+++ b/lib/vauth/krb5_sspi.c
@@ -270,6 +270,10 @@ CURLcode Curl_auth_create_gssapi_security_message(struct Curl_easy *data,
   SECURITY_STATUS status;
   char *user_name;
 
+#if defined(CURL_DISABLE_VERBOSE_STRINGS)
+  (void) data;
+#endif
+
   /* Ensure we have a valid challenge message */
   if(!Curl_bufref_len(chlg)) {
     infof(data, "GSSAPI handshake failure (empty security message)");
diff --git a/lib/vauth/ntlm_sspi.c b/lib/vauth/ntlm_sspi.c
index b078c8249..3e39dad31 100644
--- a/lib/vauth/ntlm_sspi.c
+++ b/lib/vauth/ntlm_sspi.c
@@ -253,6 +253,9 @@ CURLcode Curl_auth_create_ntlm_type3_message(struct Curl_easy *data,
   unsigned long attrs;
   TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */
 
+#if defined(CURL_DISABLE_VERBOSE_STRINGS)
+  (void) data;
+#endif
   (void) passwdp;
   (void) userp;