diff --git a/src/common.h b/src/common.h
index 238af79..18390f3 100644
--- a/src/common.h
+++ b/src/common.h
@@ -116,6 +116,7 @@ void *memrchr( const void *s, int c, size_t n );
 #endif
 
 int starts_with( const char *str, int strl, const char *cmp, int cmpl );
+int starts_with_upper( const char *str, int strl, const char *cmp, int cmpl );
 int equals( const char *str, int strl, const char *cmp, int cmpl );
 
 #ifndef HAVE_TIMEGM
diff --git a/src/drv_imap.c b/src/drv_imap.c
index a0c13e0..608a2d3 100644
--- a/src/drv_imap.c
+++ b/src/drv_imap.c
@@ -967,7 +967,7 @@ parse_fetch_rsp( imap_store_t *ctx, list_t *list, char *s ATTR_UNUSED )
 					tmp = tmp->next;
 					if (!is_atom( tmp ))
 						goto bfail;
-					if (starts_with( tmp->val, tmp->len, "X-TUID: ", 8 ))
+					if (starts_with_upper( tmp->val, tmp->len, "X-TUID: ", 8 ))
 						tuid = tmp->val + 8;
 				} else {
 				  bfail:
diff --git a/src/sync.c b/src/sync.c
index eb444e0..4fb2026 100644
--- a/src/sync.c
+++ b/src/sync.c
@@ -338,7 +338,7 @@ msg_fetched( int sts, void *aux )
 					if (c == '\r')
 						lcrs++;
 					else if (c == '\n') {
-						if (starts_with( fmap + start, len - start, "X-TUID: ", 8 )) {
+						if (starts_with_upper( fmap + start, len - start, "X-TUID: ", 8 )) {
 							extra = (sbreak = start) - (ebreak = i);
 							goto oke;
 						}
diff --git a/src/util.c b/src/util.c
index 6851c6f..f05eec6 100644
--- a/src/util.c
+++ b/src/util.c
@@ -27,6 +27,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
+#include <ctype.h>
 #include <pwd.h>
 
 static int need_nl;
@@ -241,6 +242,21 @@ starts_with( const char *str, int strl, const char *cmp, int cmpl )
 	return (strl >= cmpl) && !memcmp( str, cmp, cmpl );
 }
 
+int
+starts_with_upper( const char *str, int strl, const char *cmp, int cmpl )
+{
+	int i;
+
+	if (strl < 0)
+		strl = strnlen( str, cmpl + 1 );
+	if (strl < cmpl)
+		return 0;
+	for (i = 0; i < cmpl; i++)
+		if (str[i] != cmp[i] && toupper( str[i] ) != cmp[i])
+			return 0;
+	return 1;
+}
+
 int
 equals( const char *str, int strl, const char *cmp, int cmpl )
 {