diff --git a/block/bochs.c b/block/bochs.c
index 51d9a905772e1f989abc018910178d90bb8a4b70..4d6403f9040f19ad03d02ec74869e28e14779973 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -129,7 +129,8 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
         strcmp(bochs.subtype, GROWING_TYPE) ||
 	((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
 	(le32_to_cpu(bochs.version) != HEADER_V1))) {
-        return -EMEDIUMTYPE;
+        error_setg(errp, "Image not in Bochs format");
+        return -EINVAL;
     }
 
     if (le32_to_cpu(bochs.version) == HEADER_V1) {
diff --git a/block/cow.c b/block/cow.c
index 9e4f624b016063e1a08a5e5c95b9336c48b8c10f..30deb88deb734d946c4b62efd60c025d5f31612f 100644
--- a/block/cow.c
+++ b/block/cow.c
@@ -74,7 +74,8 @@ static int cow_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     if (be32_to_cpu(cow_header.magic) != COW_MAGIC) {
-        ret = -EMEDIUMTYPE;
+        error_setg(errp, "Image not in COW format");
+        ret = -EINVAL;
         goto fail;
     }
 
diff --git a/block/parallels.c b/block/parallels.c
index 2121e43204558051f661dbdc9f7b7acd787922e2..3f588f58dc23b51cab27944d30a7bda881c9abc9 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -85,7 +85,8 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
 
     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
         (le32_to_cpu(ph.version) != HEADER_VERSION)) {
-        ret = -EMEDIUMTYPE;
+        error_setg(errp, "Image not in Parallels format");
+        ret = -EINVAL;
         goto fail;
     }
 
diff --git a/block/qcow.c b/block/qcow.c
index ef8920bf07d5fa98a62d11ab29e93a0dff1e4cd6..1e128becf0347734584d25cda74c002a7933e171 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -113,7 +113,8 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
     be64_to_cpus(&header.l1_table_offset);
 
     if (header.magic != QCOW_MAGIC) {
-        ret = -EMEDIUMTYPE;
+        error_setg(errp, "Image not in qcow format");
+        ret = -EINVAL;
         goto fail;
     }
     if (header.version != QCOW_VERSION) {
diff --git a/block/qcow2.c b/block/qcow2.c
index 9dfd90896b60f50a2fa6846d1003659f13cd6570..cfe80befa05ffd19442313ad252a221de8e331bc 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -449,7 +449,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
 
     if (header.magic != QCOW_MAGIC) {
         error_setg(errp, "Image is not in qcow2 format");
-        ret = -EMEDIUMTYPE;
+        ret = -EINVAL;
         goto fail;
     }
     if (header.version < 2 || header.version > 3) {
diff --git a/block/qed.c b/block/qed.c
index 968028ecbd34e0565b48181bb840801971d6ce30..8802ad3845bcb7b5fcbc3552f552d0d7115d4735 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -391,7 +391,8 @@ static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
     qed_header_le_to_cpu(&le_header, &s->header);
 
     if (s->header.magic != QED_MAGIC) {
-        return -EMEDIUMTYPE;
+        error_setg(errp, "Image not in QED format");
+        return -EINVAL;
     }
     if (s->header.features & ~QED_FEATURE_MASK) {
         /* image uses unsupported feature bits */
diff --git a/block/vdi.c b/block/vdi.c
index 2d7490f173db0e717b0fdf3b03172f4420a39f42..f3c6acf3cf2f0b1c9469ebdceb57200db883794c 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -395,8 +395,8 @@ static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     if (header.signature != VDI_SIGNATURE) {
-        logout("bad vdi signature %08x\n", header.signature);
-        ret = -EMEDIUMTYPE;
+        error_setg(errp, "Image not in VDI format (bad signature %08x)", header.signature);
+        ret = -EINVAL;
         goto fail;
     } else if (header.version != VDI_VERSION_1_1) {
         logout("unsupported version %u.%u\n",
diff --git a/block/vmdk.c b/block/vmdk.c
index 9c3711cbbf8d7aa0a4d0c78a2d52e075ceee4934..83839f9b7a48b46a413e41d0b56c482eae1319d2 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -748,7 +748,8 @@ static int vmdk_open_sparse(BlockDriverState *bs,
             return vmdk_open_vmdk4(bs, file, flags, errp);
             break;
         default:
-            return -EMEDIUMTYPE;
+            error_setg(errp, "Image not in VMDK format");
+            return -EINVAL;
             break;
     }
 }
@@ -862,7 +863,8 @@ static int vmdk_open_desc_file(BlockDriverState *bs, int flags, char *buf,
     BDRVVmdkState *s = bs->opaque;
 
     if (vmdk_parse_description(buf, "createType", ct, sizeof(ct))) {
-        ret = -EMEDIUMTYPE;
+        error_setg(errp, "invalid VMDK image descriptor");
+        ret = -EINVAL;
         goto exit;
     }
     if (strcmp(ct, "monolithicFlat") &&
diff --git a/block/vpc.c b/block/vpc.c
index 1d326cbf44794b2f18991e259b65186f3d4d5a64..82bf2485a54da08ab01b9a476bd0e35b31599268 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -190,7 +190,8 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
             goto fail;
         }
         if (strncmp(footer->creator, "conectix", 8)) {
-            ret = -EMEDIUMTYPE;
+            error_setg(errp, "invalid VPC image");
+            ret = -EINVAL;
             goto fail;
         }
         disk_type = VHD_FIXED;