diff --git a/src/add-ons/kernel/drivers/audio/ac97/auich/multi.c b/src/add-ons/kernel/drivers/audio/ac97/auich/multi.c
index fe41dcf4ca..639ee8319d 100644
--- a/src/add-ons/kernel/drivers/audio/ac97/auich/multi.c
+++ b/src/add-ons/kernel/drivers/audio/ac97/auich/multi.c
@@ -1090,6 +1090,9 @@ auich_free(void* cookie)
 	while(!LIST_EMPTY(&card->streams)) {
 		auich_stream_delete(LIST_FIRST(&card->streams));
 	}
+
+	card->pstream = NULL;
+	card->rstream = NULL;
 	
 	return B_OK;
 }
diff --git a/src/add-ons/kernel/drivers/audio/ac97/auvia/multi.c b/src/add-ons/kernel/drivers/audio/ac97/auvia/multi.c
index c3c6c30d90..c1a7a53484 100644
--- a/src/add-ons/kernel/drivers/audio/ac97/auvia/multi.c
+++ b/src/add-ons/kernel/drivers/audio/ac97/auvia/multi.c
@@ -381,7 +381,7 @@ auvia_create_controls_list(multi_dev *multi)
 	}
 				
 	multi->control_count = index;
-	PRINT(("multi->control_count %u\n", multi->control_count));
+	PRINT(("multi->control_count %lu\n", multi->control_count));
 	return B_OK;
 }
 
@@ -393,7 +393,7 @@ auvia_get_mix(auvia_dev *card, multi_mix_value_info * MMVI)
 	for(i=0; i<MMVI->item_count; i++) {
 		id = MMVI->values[i].id - EMU_MULTI_CONTROL_FIRSTID;
 		if(id < 0 || id >= card->multi.control_count) {
-			PRINT(("auvia_get_mix : invalid control id requested : %i\n", id));
+			PRINT(("auvia_get_mix : invalid control id requested : %li\n", id));
 			continue;
 		}
 		control = &card->multi.controls[id];
@@ -432,7 +432,7 @@ auvia_set_mix(auvia_dev *card, multi_mix_value_info * MMVI)
 	for(i=0; i<MMVI->item_count; i++) {
 		id = MMVI->values[i].id - EMU_MULTI_CONTROL_FIRSTID;
 		if(id < 0 || id >= card->multi.control_count) {
-			PRINT(("auvia_set_mix : invalid control id requested : %i\n", id));
+			PRINT(("auvia_set_mix : invalid control id requested : %li\n", id));
 			continue;
 		}
 		control = &card->multi.controls[id];
@@ -442,7 +442,7 @@ auvia_set_mix(auvia_dev *card, multi_mix_value_info * MMVI)
 			if(i+1<MMVI->item_count) {
 				id = MMVI->values[i + 1].id - EMU_MULTI_CONTROL_FIRSTID;
 				if(id < 0 || id >= card->multi.control_count) {
-					PRINT(("auvia_set_mix : invalid control id requested : %i\n", id));
+					PRINT(("auvia_set_mix : invalid control id requested : %li\n", id));
 				} else {
 					control2 = &card->multi.controls[id];
 					if(control2->mix_control.master != control->mix_control.id)
@@ -1098,6 +1098,9 @@ auvia_free(void* cookie)
 	while(!LIST_EMPTY(&card->streams)) {
 		auvia_stream_delete(LIST_FIRST(&card->streams));
 	}
+
+	card->pstream = NULL;
+	card->rstream = NULL;
 	
 	return B_OK;
 }
diff --git a/src/add-ons/kernel/drivers/audio/echo/multi.cpp b/src/add-ons/kernel/drivers/audio/echo/multi.cpp
index 240016ab58..2d9e81f8f6 100644
--- a/src/add-ons/kernel/drivers/audio/echo/multi.cpp
+++ b/src/add-ons/kernel/drivers/audio/echo/multi.cpp
@@ -992,6 +992,9 @@ echo_free(void* cookie)
 	while(!LIST_EMPTY(&card->streams)) {
 		echo_stream_delete(LIST_FIRST(&card->streams));
 	}
+
+	card->pstream = NULL;
+	card->rstream = NULL;
 	
 	return B_OK;
 }
diff --git a/src/add-ons/kernel/drivers/audio/emuxki/multi.c b/src/add-ons/kernel/drivers/audio/emuxki/multi.c
index db25462755..0bfe1d45ee 100644
--- a/src/add-ons/kernel/drivers/audio/emuxki/multi.c
+++ b/src/add-ons/kernel/drivers/audio/emuxki/multi.c
@@ -1262,6 +1262,11 @@ emuxki_free(void* cookie)
 	while(!LIST_EMPTY(&card->streams)) {
 		emuxki_stream_delete(LIST_FIRST(&card->streams));
 	}
+
+	card->pstream = NULL;
+	card->pstream2 = NULL;
+	card->rstream = NULL;
+	card->rstream2 = NULL;
 	
 	return B_OK;
 }