diff --git a/libmount/src/cache.c b/libmount/src/cache.c
index 2a8077c3a..b718fd5d4 100644
--- a/libmount/src/cache.c
+++ b/libmount/src/cache.c
@@ -258,6 +258,7 @@ int mnt_cache_read_tags(struct libmnt_cache *cache, const char *devname)
 {
 	blkid_probe pr;
 	size_t i, ntags = 0;
+	int rc;
 	const char *tags[] = { "LABEL", "UUID", "TYPE", "PARTUUID", "PARTLABEL" };
 	const char *blktags[] = { "LABEL", "UUID", "TYPE", "PART_ENTRY_UUID", "PART_ENTRY_NAME" };
 
@@ -291,7 +292,8 @@ int mnt_cache_read_tags(struct libmnt_cache *cache, const char *devname)
 	blkid_probe_enable_partitions(pr, 1);
 	blkid_probe_set_partitions_flags(pr, BLKID_PARTS_ENTRY_DETAILS);
 
-	if (blkid_do_safeprobe(pr))
+	rc = blkid_do_safeprobe(pr);
+	if (rc)
 		goto error;
 
 	DBG(CACHE, mnt_debug_h(cache, "reading tags for: %s", devname));
@@ -323,7 +325,7 @@ int mnt_cache_read_tags(struct libmnt_cache *cache, const char *devname)
 	return ntags ? 0 : 1;
 error:
 	blkid_free_probe(pr);
-	return -1;
+	return rc < 0 ? rc : -1;
 }
 
 /**
@@ -347,6 +349,22 @@ int mnt_cache_device_has_tag(struct libmnt_cache *cache, const char *devname,
 	return 0;
 }
 
+static int __mnt_cache_find_tag_value(struct libmnt_cache *cache,
+		const char *devname, const char *token, char **data)
+{
+	int rc = 0;
+
+	if (!cache || !devname || !token || !data)
+		return -EINVAL;
+
+	rc = mnt_cache_read_tags(cache, devname);
+	if (rc)
+		return rc;
+
+	*data = cache_find_tag_value(cache, devname, token);
+	return data ? 0 : -1;
+}
+
 /**
  * mnt_cache_find_tag_value:
  * @cache: cache for results
@@ -358,13 +376,11 @@ int mnt_cache_device_has_tag(struct libmnt_cache *cache, const char *devname,
 char *mnt_cache_find_tag_value(struct libmnt_cache *cache,
 		const char *devname, const char *token)
 {
-	if (!cache || !devname || !token)
-		return NULL;
+	char *data = NULL;
 
-	if (mnt_cache_read_tags(cache, devname) != 0)
-		return NULL;
-
-	return cache_find_tag_value(cache, devname, token);
+	if (__mnt_cache_find_tag_value(cache, devname, token, &data) == 0)
+		return data;
+	return NULL;
 }
 
 /**
@@ -385,8 +401,13 @@ char *mnt_get_fstype(const char *devname, int *ambi, struct libmnt_cache *cache)
 
 	DBG(CACHE, mnt_debug_h(cache, "get %s FS type", devname));
 
-	if (cache)
-		return mnt_cache_find_tag_value(cache, devname, "TYPE");
+	if (cache) {
+		char *val = NULL;
+		rc = __mnt_cache_find_tag_value(cache, devname, "TYPE", &val);
+		if (ambi)
+			*ambi = rc == -2 ? TRUE : FALSE;
+		return rc ? NULL : val;
+	}
 
 	/*
 	 * no cache, probe directly
@@ -396,11 +417,12 @@ char *mnt_get_fstype(const char *devname, int *ambi, struct libmnt_cache *cache)
 		return NULL;
 
 	blkid_probe_enable_superblocks(pr, 1);
-
 	blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_TYPE);
 
 	rc = blkid_do_safeprobe(pr);
 
+	DBG(CACHE, mnt_debug_h(cache, "liblkid rc=%d", rc));
+
 	if (!rc && !blkid_probe_lookup_value(pr, "TYPE", &data, NULL))
 		type = strdup(data);
 
diff --git a/libmount/src/context.c b/libmount/src/context.c
index 6d5703834..2e2a161dd 100644
--- a/libmount/src/context.c
+++ b/libmount/src/context.c
@@ -146,7 +146,6 @@ int mnt_reset_context(struct libmnt_context *cxt)
 
 	cxt->fs = NULL;
 	cxt->mtab = NULL;
-	cxt->ambi = 0;
 	cxt->helper = NULL;
 	cxt->orig_user = NULL;
 	cxt->mountflags = 0;
@@ -1514,13 +1513,16 @@ int mnt_context_guess_fstype(struct libmnt_context *cxt)
 
 	if (access(dev, F_OK) == 0) {
 		struct libmnt_cache *cache = mnt_context_get_cache(cxt);
+		int ambi = 0;
 
-		type = mnt_get_fstype(dev, &cxt->ambi, cache);
+		type = mnt_get_fstype(dev, &ambi, cache);
 		if (type) {
 			rc = mnt_fs_set_fstype(cxt->fs, type);
 			if (!cache)
 				free(type);	/* type is not cached */
 		}
+		if (ambi)
+			rc = -MNT_ERR_AMBIFS;
 	} else {
 		if (strchr(dev, ':') != NULL)
 			rc = mnt_fs_set_fstype(cxt->fs, "nfs");
@@ -1529,7 +1531,8 @@ int mnt_context_guess_fstype(struct libmnt_context *cxt)
 	}
 
 done:
-	DBG(CXT, mnt_debug_h(cxt, "FS type: %s", mnt_fs_get_fstype(cxt->fs)));
+	DBG(CXT, mnt_debug_h(cxt, "FS type: %s [rc=%d]",
+				mnt_fs_get_fstype(cxt->fs), rc));
 	return rc;
 none:
 	return mnt_fs_set_fstype(cxt->fs, "none");
diff --git a/libmount/src/mountP.h b/libmount/src/mountP.h
index 0fe5b1d86..8eb677cdc 100644
--- a/libmount/src/mountP.h
+++ b/libmount/src/mountP.h
@@ -338,7 +338,6 @@ struct libmnt_context
 	int		utab_writable; /* is utab writable */
 
 	int	flags;		/* private context flags */
-	int	ambi;		/* libblkid returns ambivalent result */
 
 	char	*helper;	/* name of the used /sbin/[u]mount.<type> helper */
 	int	helper_status;	/* helper wait(2) status */
diff --git a/sys-utils/mount.c b/sys-utils/mount.c
index 0c74ed900..ebdfe885d 100644
--- a/sys-utils/mount.c
+++ b/sys-utils/mount.c
@@ -385,6 +385,11 @@ try_readonly:
 				warnx(_("can't find mount source %s in %s"),
 						src, mnt_get_fstab_path());
 			return MOUNT_EX_USAGE;
+		case -MNT_ERR_AMBIFS:
+			warnx(_("%s: more filesystems detected. This should not happen,\n"
+			  "       use -t <type> to explicitly specify the filesystem type or\n"
+			  "       use wipefs(8) to clean up the device."), src);
+			return MOUNT_EX_USAGE;
 		case -MNT_ERR_NOFSTYPE:
 			if (restricted)
 				warnx(_("I could not determine the filesystem type, "