diff --git a/rtengine/myfile.h b/rtengine/myfile.h
index c8ed35a85..2222eab37 100644
--- a/rtengine/myfile.h
+++ b/rtengine/myfile.h
@@ -44,6 +44,7 @@ inline int feof (IMFILE* f) {
 }
 
 inline void fseek (IMFILE* f, int p, int how) {
+	int fpos = f->pos;
 
 	if (how==SEEK_SET)
 		f->pos = p;
@@ -51,6 +52,9 @@ inline void fseek (IMFILE* f, int p, int how) {
 		f->pos += p;
 	else if (how==SEEK_END)
 		f->pos = f->size-p;
+
+	if (f->pos < 0  || f->pos> f->size)
+		f->pos = fpos;
 }
 
 inline int fgetc (IMFILE* f) {