diff --git a/src/data-compat.c b/src/data-compat.c
index 830b42c6..9091b968 100644
--- a/src/data-compat.c
+++ b/src/data-compat.c
@@ -48,8 +48,8 @@ gpgme_data_new_from_filepart (gpgme_data_t *r_dh, const char *fname,
   int res;
 
   TRACE_BEG  (DEBUG_DATA, "gpgme_data_new_from_filepart", r_dh,
-	      "file_name=%s, stream=%p, offset=%lli, length=%u",
-	      fname, stream, offset, length);
+	      "file_name=%s, stream=%p, offset=%lli, length=%zu",
+	      fname, stream, (long long int)offset, length);
 
   if (stream && fname)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
@@ -173,13 +173,13 @@ old_user_read (gpgme_data_t dh, void *buffer, size_t size)
   gpgme_error_t err;
   size_t amt;
   TRACE_BEG  (DEBUG_DATA, "gpgme:old_user_read", dh,
-	      "buffer=%p, size=%u", buffer, size);
+	      "buffer=%p, size=%zu", buffer, size);
 
   err = (*dh->data.old_user.cb) (dh->data.old_user.handle,
 				 buffer, size, &amt);
   if (err)
     return TRACE_SYSRES (gpgme_error_to_errno (err));
-  return TRACE_SYSRES ((gpgme_ssize_t)amt);
+  return TRACE_SYSRES ((int)amt);
 }
 
 
@@ -188,7 +188,7 @@ old_user_seek (gpgme_data_t dh, gpgme_off_t offset, int whence)
 {
   gpgme_error_t err;
   TRACE_BEG  (DEBUG_DATA, "gpgme:old_user_seek", dh,
-	      "offset=%llu, whence=%i", offset, whence);
+	      "offset=%llu, whence=%i", (long long int)offset, whence);
 
   if (whence != SEEK_SET || offset)
     {
diff --git a/src/data-mem.c b/src/data-mem.c
index c461a606..915c3e00 100644
--- a/src/data-mem.c
+++ b/src/data-mem.c
@@ -190,7 +190,7 @@ gpgme_data_new_from_mem (gpgme_data_t *r_dh, const char *buffer,
 {
   gpgme_error_t err;
   TRACE_BEG  (DEBUG_DATA, "gpgme_data_new_from_mem", r_dh,
-	      "buffer=%p, size=%u, copy=%i (%s)", buffer, size,
+	      "buffer=%p, size=%zu, copy=%i (%s)", buffer, size,
 	      copy, copy ? "yes" : "no");
 
   err = _gpgme_data_new (r_dh, &mem_cbs);
@@ -283,7 +283,7 @@ gpgme_data_release_and_get_mem (gpgme_data_t dh, size_t *r_len)
 
   if (r_len)
     {
-      TRACE_SUC ("buffer=%p, len=%u", str, *r_len);
+      TRACE_SUC ("buffer=%p, len=%zu", str, *r_len);
     }
   else
     {
diff --git a/src/data.c b/src/data.c
index f633e08c..44ef2d3d 100644
--- a/src/data.c
+++ b/src/data.c
@@ -353,7 +353,7 @@ gpgme_data_read (gpgme_data_t dh, void *buffer, size_t size)
   gpgme_ssize_t res;
   int blankout;
   TRACE_BEG  (DEBUG_DATA, "gpgme_data_read", dh,
-	      "buffer=%p, size=%u", buffer, size);
+	      "buffer=%p, size=%zu", buffer, size);
 
   if (!dh)
     {
@@ -376,7 +376,7 @@ gpgme_data_read (gpgme_data_t dh, void *buffer, size_t size)
       while (res < 0 && errno == EINTR);
     }
 
-  return TRACE_SYSRES (res);
+  return TRACE_SYSRES ((int)res);
 }
 
 
@@ -388,7 +388,7 @@ gpgme_data_write (gpgme_data_t dh, const void *buffer, size_t size)
 {
   gpgme_ssize_t res;
   TRACE_BEG  (DEBUG_DATA, "gpgme_data_write", dh,
-	      "buffer=%p, size=%u", buffer, size);
+	      "buffer=%p, size=%zu", buffer, size);
 
   if (!dh)
     {
@@ -404,7 +404,7 @@ gpgme_data_write (gpgme_data_t dh, const void *buffer, size_t size)
     res = (*dh->cbs->write) (dh, buffer, size);
   while (res < 0 && errno == EINTR);
 
-  return TRACE_SYSRES (res);
+  return TRACE_SYSRES ((int)res);
 }
 
 
@@ -415,7 +415,7 @@ gpgme_off_t
 gpgme_data_seek (gpgme_data_t dh, gpgme_off_t offset, int whence)
 {
   TRACE_BEG  (DEBUG_DATA, "gpgme_data_seek", dh,
-	      "offset=%lli, whence=%i", offset, whence);
+	      "offset=%lli, whence=%i", (long long int)offset, whence);
 
   if (!dh)
     {
@@ -437,7 +437,7 @@ gpgme_data_seek (gpgme_data_t dh, gpgme_off_t offset, int whence)
   if (offset >= 0)
     dh->pending_len = 0;
 
-  return TRACE_SYSRES (offset);
+  return TRACE_SYSRES ((int)offset);
 }
 
 
diff --git a/src/debug.c b/src/debug.c
index 29f7dc6d..f0b0da0e 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -379,7 +379,7 @@ _gpgme_debug_end (void **line)
 
   /* The smallest possible level is 1, so force logging here by
      using that.  */
-  _gpgme_debug (1, -1, NULL, NULL, NULL, "%s", *line);
+  _gpgme_debug (1, -1, NULL, NULL, NULL, "%s", (char*)*line);
   gpgrt_free (*line);
   *line = NULL;
 }
diff --git a/src/gpgme.c b/src/gpgme.c
index ac98bd59..c4a1da11 100644
--- a/src/gpgme.c
+++ b/src/gpgme.c
@@ -911,7 +911,7 @@ gpgme_io_read (int fd, void *buffer, size_t count)
 {
   int ret;
   TRACE_BEG  (DEBUG_GLOBAL, "gpgme_io_read", fd,
-	      "buffer=%p, count=%u", buffer, count);
+	      "buffer=%p, count=%zu", buffer, count);
 
   ret = _gpgme_io_read (fd, buffer, count);
 
@@ -927,7 +927,7 @@ gpgme_io_write (int fd, const void *buffer, size_t count)
 {
   int ret;
   TRACE_BEG  (DEBUG_GLOBAL, "gpgme_io_write", fd,
-	      "buffer=%p, count=%u", buffer, count);
+	      "buffer=%p, count=%zu", buffer, count);
 
   ret = _gpgme_io_write (fd, buffer, count);
 
@@ -946,7 +946,7 @@ gpgme_io_writen (int fd, const void *buffer_arg, size_t count)
   const char *buffer = buffer_arg;
   int ret = 0;
   TRACE_BEG  (DEBUG_GLOBAL, "gpgme_io_writen", fd,
-	      "buffer=%p, count=%u", buffer, count);
+	      "buffer=%p, count=%zu", buffer, count);
   while (count)
     {
       ret = _gpgme_io_write (fd, buffer, count);
diff --git a/src/import.c b/src/import.c
index 3d49146f..2834aec2 100644
--- a/src/import.c
+++ b/src/import.c
@@ -103,7 +103,8 @@ gpgme_op_import_result (gpgme_ctx_t ctx)
       while (impstat)
 	{
 	  TRACE_LOG  ("import[%i] for %s = 0x%x (%s)",
-		      i, impstat->fpr, impstat->status, impstat->result);
+		      i, impstat->fpr, impstat->status,
+                      gpgme_strerror (impstat->result));
 	  impstat = impstat->next;
 	  i++;
 	}
diff --git a/src/posix-io.c b/src/posix-io.c
index 78f523b1..77ecde05 100644
--- a/src/posix-io.c
+++ b/src/posix-io.c
@@ -110,7 +110,7 @@ _gpgme_io_read (int fd, void *buffer, size_t count)
 {
   int nread;
   TRACE_BEG  (DEBUG_SYSIO, "_gpgme_io_read", fd,
-	      "buffer=%p, count=%u", buffer, count);
+	      "buffer=%p, count=%zu", buffer, count);
 
   do
     {
@@ -128,7 +128,7 @@ _gpgme_io_write (int fd, const void *buffer, size_t count)
 {
   int nwritten;
   TRACE_BEG  (DEBUG_SYSIO, "_gpgme_io_write", fd,
-	      "buffer=%p, count=%u", buffer, count);
+	      "buffer=%p, count=%zu", buffer, count);
   TRACE_LOGBUFX (buffer, count);
 
   do
@@ -427,7 +427,7 @@ get_max_fds (void)
     }
 #endif
 
-  TRACE (DEBUG_SYSIO, "gpgme:max_fds", 0, "max fds=%i (%s)", fds, source);
+  TRACE (DEBUG_SYSIO, "gpgme:max_fds", 0, "max fds=%ld (%s)", fds, source);
   return fds;
 }
 
@@ -654,7 +654,7 @@ _gpgme_io_select (struct io_select_fd_s *fds, size_t nfds, int nonblock)
   struct timeval timeout = { 1, 0 };
   void *dbg_help = NULL;
   TRACE_BEG  (DEBUG_SYSIO, "_gpgme_io_select", fds,
-	      "nfds=%u, nonblock=%u", nfds, nonblock);
+	      "nfds=%zu, nonblock=%u", nfds, nonblock);
 
   FD_ZERO (&readfds);
   FD_ZERO (&writefds);
diff --git a/src/queryswdb.c b/src/queryswdb.c
index e72dabbc..2b7a07f5 100644
--- a/src/queryswdb.c
+++ b/src/queryswdb.c
@@ -92,7 +92,7 @@ gpgme_op_query_swdb (gpgme_ctx_t ctx, const char *name, const char *iversion,
   op_data_t opd;
 
   TRACE_BEG  (DEBUG_CTX, "gpgme_op_query_swdb", ctx,
-	      "name=%s, iversion=%", name, iversion);
+	      "name=%s, iversion=%s", name, iversion);
 
   if (!ctx || reserved)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
diff --git a/src/trustlist.c b/src/trustlist.c
index c7778379..a0e82385 100644
--- a/src/trustlist.c
+++ b/src/trustlist.c
@@ -246,20 +246,20 @@ gpgme_op_trustlist_next (gpgme_ctx_t ctx, gpgme_trust_item_t *r_item)
   if ((*r_item)->type == 1)
     {
       TRACE_SUC ("trust_item=%p: %s: owner trust %s with level %i "
-		  "and validity 0x%x", *r_item, (*r_item)->keyid,
+		  "and validity %s", *r_item, (*r_item)->keyid,
 		  (*r_item)->owner_trust, (*r_item)->level,
 		  (*r_item)->validity);
     }
   else if ((*r_item)->type == 2)
     {
       TRACE_SUC ("trust_item=%p: %s: UID %s with level %i "
-		  "and validity 0x%x", *r_item, (*r_item)->keyid,
+		  "and validity %s", *r_item, (*r_item)->keyid,
 		  (*r_item)->name, (*r_item)->level, (*r_item)->validity);
     }
   else
     {
       TRACE_SUC ("trust_item=%p: %s: unknown type %i with level %i "
-		  "and validity 0x%x", *r_item, (*r_item)->keyid,
+		  "and validity %s", *r_item, (*r_item)->keyid,
 		  (*r_item)->type, (*r_item)->level, (*r_item)->validity);
     }
   return 0;
diff --git a/src/verify.c b/src/verify.c
index 78e549ed..8aa9d281 100644
--- a/src/verify.c
+++ b/src/verify.c
@@ -135,7 +135,7 @@ gpgme_op_verify_result (gpgme_ctx_t ctx)
 	{
 	  TRACE_LOG  ("sig[%i] = fpr %s, summary 0x%x, status %s",
 		      i, sig->fpr, sig->summary, gpg_strerror (sig->status));
-	  TRACE_LOG  ("sig[%i] = timestamps 0x%x/0x%x flags:%s%s%s",
+	  TRACE_LOG  ("sig[%i] = timestamps 0x%lx/0x%lx flags:%s%s%s",
 		      i, sig->timestamp, sig->exp_timestamp,
 		      sig->wrong_key_usage ? "wrong key usage" : "",
 		      sig->pka_trust == 1 ? "pka bad"
diff --git a/src/version.c b/src/version.c
index 8c35ed0e..3bf12e94 100644
--- a/src/version.c
+++ b/src/version.c
@@ -230,14 +230,14 @@ gpgme_check_version_internal (const char *req_version,
 
   /* Catch-22, see above.  */
   TRACE (DEBUG_INIT, "gpgme_check_version_internal", 0,
-	  "req_version=%s, offset_sig_validity=%i",
+	  "req_version=%s, offset_sig_validity=%zu",
 	  req_version ? req_version : "(null)", offset_sig_validity);
 
   if (offset_sig_validity != offsetof (struct _gpgme_signature, validity))
     {
       TRACE (DEBUG_INIT, "gpgme_check_version_internal", 0,
 	      "offset_sig_validity mismatch: expected %i",
-	      offsetof (struct _gpgme_signature, validity));
+             (int)offsetof (struct _gpgme_signature, validity));
       _gpgme_selftest = GPG_ERR_SELFTEST_FAILED;
     }