diff --git a/cmd/dotmesh-server/s3.go b/cmd/dotmesh-server/s3.go
index f3924b996..4e0eafe35 100644
--- a/cmd/dotmesh-server/s3.go
+++ b/cmd/dotmesh-server/s3.go
@@ -115,17 +115,20 @@ func getS3Client(transferRequest S3TransferRequest) (*s3.S3, error) {
 }
 
 func downloadS3Bucket(svc *s3.S3, bucketName, destPath, transferRequestId string, prefixes []string, pollResult *TransferPollResult, currentKeyVersions map[string]string) (bool, map[string]string, error) {
+	log.Printf("Prefixes: %#v, len: %d", prefixes, len(prefixes))
 	if len(prefixes) == 0 {
 		return downloadPartialS3Bucket(svc, bucketName, destPath, transferRequestId, "", pollResult, currentKeyVersions)
 	}
 	var changed bool
 	var err error
 	for _, prefix := range prefixes {
+		log.Printf("[downloadS3Bucket] Pulling down objects prefixed %s", prefix)
 		changed, currentKeyVersions, err = downloadPartialS3Bucket(svc, bucketName, destPath, transferRequestId, prefix, pollResult, currentKeyVersions)
 		if err != nil {
 			return false, nil, err
 		}
 	}
+	fmt.Printf("[downloadS3Bucket] currentVersions: %#v", currentKeyVersions)
 	return changed, currentKeyVersions, nil
 }
 
@@ -135,14 +138,13 @@ func downloadPartialS3Bucket(svc *s3.S3, bucketName, destPath, transferRequestId
 	// 2. Download new versions of things that have changed
 	// 3. Return a map of object key -> s3 version id, plus an indicator of whether anything actually changed during this process so we know whether to make a snapshot.
 	var bucketChanged bool
-	// TODO refactor this a lil so we can get the folder structure easily
-	fmt.Printf("[downloadS3Bucket] currentVersions: %#v", currentKeyVersions)
 	params := &s3.ListObjectVersionsInput{
 		Bucket: aws.String(bucketName),
 	}
 	if prefix != "" {
-		params.Prefix = prefix
+		params.SetPrefix(prefix)
 	}
+	log.Printf("Params: %#v", *params)
 	downloader := s3manager.NewDownloaderWithClient(svc)
 	var innerError error
 	err := svc.ListObjectVersionsPages(params,
@@ -203,7 +205,7 @@ func downloadPartialS3Bucket(svc *s3.S3, bucketName, destPath, transferRequestId
 	} else if innerError != nil {
 		return bucketChanged, nil, innerError
 	}
-	fmt.Printf("New key versions: %#v", currentKeyVersions)
+	fmt.Printf("[downloadPartialS3Bucket] New key versions: %#v", currentKeyVersions)
 	return bucketChanged, currentKeyVersions, nil
 }
 
diff --git a/cmd/dotmesh-server/transfers.go b/cmd/dotmesh-server/transfers.go
index f8aaaaa44..148454e7c 100644
--- a/cmd/dotmesh-server/transfers.go
+++ b/cmd/dotmesh-server/transfers.go
@@ -15,11 +15,16 @@ func s3TransferRequestify(in interface{}) (S3TransferRequest, error) {
 			"Unable to cast %s to map[string]interface{}", in,
 		)
 	}
+	prefixInter, ok := typed["Prefixes"].([]interface{})
+	var prefixes []string
+	for _, pref := range prefixInter {
+		prefixes = append(prefixes, pref.(string))
+	}
 	return S3TransferRequest{
 		KeyID:           typed["KeyID"].(string),
 		SecretKey:       typed["SecretKey"].(string),
 		Endpoint:        typed["Endpoint"].(string),
-		Prefixes:        typed["Prefixes"].([]string),
+		Prefixes:        prefixes,
 		Direction:       typed["Direction"].(string),
 		LocalNamespace:  typed["LocalNamespace"].(string),
 		LocalName:       typed["LocalName"].(string),