Index: source/blender/imbuf/intern/tiff.c
===================================================================
--- source/blender/imbuf/intern/tiff.c	(revision 58159)
+++ source/blender/imbuf/intern/tiff.c	(working copy)
@@ -575,9 +575,9 @@
 		if (spp == 4) {
 			unsigned short extra, *extraSampleTypes;
 
-			TIFFGetField(image, TIFFTAG_EXTRASAMPLES, &extra, &extraSampleTypes);
+			int got_field = TIFFGetField(image, TIFFTAG_EXTRASAMPLES, &extra, &extraSampleTypes);
 
-			if (extraSampleTypes[0] == EXTRASAMPLE_ASSOCALPHA)
+			if (got_field && extraSampleTypes[0] == EXTRASAMPLE_ASSOCALPHA)
 				ibuf->flags |= IB_alphamode_premul;
 		}
 	}