diff --git a/cmd/godoc/godoc_test.go b/cmd/godoc/godoc_test.go
index fe87128d51..a2552d9dd7 100644
--- a/cmd/godoc/godoc_test.go
+++ b/cmd/godoc/godoc_test.go
@@ -154,19 +154,32 @@ func waitForServerReady(t *testing.T, addr string) {
 	waitForServer(t,
 		fmt.Sprintf("http://%v/", addr),
 		"The Go Programming Language",
-		15*time.Second)
+		15*time.Second,
+		false)
 }
 
 func waitForSearchReady(t *testing.T, addr string) {
 	waitForServer(t,
 		fmt.Sprintf("http://%v/search?q=FALLTHROUGH", addr),
 		"The list of tokens.",
-		2*time.Minute)
+		2*time.Minute,
+		false)
+}
+
+func waitUntilScanComplete(t *testing.T, addr string) {
+	waitForServer(t,
+		fmt.Sprintf("http://%v/pkg", addr),
+		"Scan is not yet complete",
+		2*time.Minute,
+		true,
+	)
+	// setting reverse as true, which means this waits
+	// until the string is not returned in the response anymore
 }
 
 const pollInterval = 200 * time.Millisecond
 
-func waitForServer(t *testing.T, url, match string, timeout time.Duration) {
+func waitForServer(t *testing.T, url, match string, timeout time.Duration, reverse bool) {
 	// "health check" duplicated from x/tools/cmd/tipgodoc/tip.go
 	deadline := time.Now().Add(timeout)
 	for time.Now().Before(deadline) {
@@ -177,9 +190,13 @@ func waitForServer(t *testing.T, url, match string, timeout time.Duration) {
 		}
 		rbody, err := ioutil.ReadAll(res.Body)
 		res.Body.Close()
-		if err == nil && res.StatusCode == http.StatusOK &&
-			bytes.Contains(rbody, []byte(match)) {
-			return
+		if err == nil && res.StatusCode == http.StatusOK {
+			if bytes.Contains(rbody, []byte(match)) && !reverse {
+				return
+			}
+			if !bytes.Contains(rbody, []byte(match)) && reverse {
+				return
+			}
 		}
 	}
 	t.Fatalf("Server failed to respond in %v", timeout)
@@ -229,6 +246,7 @@ func testWeb(t *testing.T, withIndex bool) {
 		waitForSearchReady(t, addr)
 	} else {
 		waitForServerReady(t, addr)
+		waitUntilScanComplete(t, addr)
 	}
 
 	tests := []struct {
diff --git a/cmd/godoc/main.go b/cmd/godoc/main.go
index 227e29b148..901e992a15 100644
--- a/cmd/godoc/main.go
+++ b/cmd/godoc/main.go
@@ -153,6 +153,13 @@ func handleURLFlag() {
 	log.Fatalf("too many redirects")
 }
 
+func initCorpus(corpus *godoc.Corpus) {
+	err := corpus.Init()
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
 func main() {
 	flag.Usage = usage
 	flag.Parse()
@@ -231,8 +238,10 @@ func main() {
 		corpus.IndexEnabled = true
 	}
 	if *writeIndex || httpMode || *urlFlag != "" {
-		if err := corpus.Init(); err != nil {
-			log.Fatal(err)
+		if httpMode {
+			go initCorpus(corpus)
+		} else {
+			initCorpus(corpus)
 		}
 	}
 
@@ -323,6 +332,9 @@ func main() {
 		}
 
 		// Start http server.
+		if *verbose {
+			log.Println("starting HTTP server")
+		}
 		if err := http.ListenAndServe(*httpAddr, handler); err != nil {
 			log.Fatalf("ListenAndServe %s: %v", *httpAddr, err)
 		}
diff --git a/godoc/corpus.go b/godoc/corpus.go
index f2c7ebbf37..8e38365a95 100644
--- a/godoc/corpus.go
+++ b/godoc/corpus.go
@@ -7,6 +7,7 @@ package godoc
 import (
 	"errors"
 	pathpkg "path"
+	"sync"
 	"time"
 
 	"golang.org/x/tools/godoc/analysis"
@@ -103,6 +104,10 @@ type Corpus struct {
 
 	// Analysis is the result of type and pointer analysis.
 	Analysis analysis.Result
+
+	// flag to check whether a corpus is initialized or not
+	initMu   sync.RWMutex
+	initDone bool
 }
 
 // NewCorpus returns a new Corpus from a filesystem.
@@ -136,13 +141,15 @@ func (c *Corpus) FSModifiedTime() time.Time {
 // Init initializes Corpus, once options on Corpus are set.
 // It must be called before any subsequent method calls.
 func (c *Corpus) Init() error {
-	// TODO(bradfitz): do this in a goroutine because newDirectory might block for a long time?
-	// It used to be sometimes done in a goroutine before, at least in HTTP server mode.
 	if err := c.initFSTree(); err != nil {
 		return err
 	}
 	c.updateMetadata()
 	go c.refreshMetadataLoop()
+
+	c.initMu.Lock()
+	c.initDone = true
+	c.initMu.Unlock()
 	return nil
 }
 
diff --git a/godoc/server.go b/godoc/server.go
index 3b452e5eda..3ebff5c52d 100644
--- a/godoc/server.go
+++ b/godoc/server.go
@@ -7,6 +7,7 @@ package godoc
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"go/ast"
 	"go/build"
@@ -248,6 +249,12 @@ func (h *handlerServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	relpath := pathpkg.Clean(r.URL.Path[len(h.stripPrefix)+1:])
+
+	if !h.corpusInitialized() {
+		h.p.ServeError(w, r, relpath, errors.New("Scan is not yet complete. Please retry after a few moments"))
+		return
+	}
+
 	abspath := pathpkg.Join(h.fsRoot, relpath)
 	mode := h.p.GetPageInfoMode(r)
 	if relpath == builtinPkgPath {
@@ -322,6 +329,12 @@ func (h *handlerServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+func (h *handlerServer) corpusInitialized() bool {
+	h.c.initMu.RLock()
+	defer h.c.initMu.RUnlock()
+	return h.c.initDone
+}
+
 type PageInfoMode uint
 
 const (