diff --git a/cmd/lotus-storage-miner/info.go b/cmd/lotus-storage-miner/info.go
index 864050170..aed867c1e 100644
--- a/cmd/lotus-storage-miner/info.go
+++ b/cmd/lotus-storage-miner/info.go
@@ -68,7 +68,7 @@ var infoCmd = &cli.Command{
 		if err != nil {
 			return err
 		}
-		pdiff := ppe-head.Height()
+		pdiff := int64(ppe-head.Height())
 		pdifft := pdiff * build.BlockDelay
 		fmt.Printf("Proving Period: %d, in %d Blocks (~%dm %ds)\n", ppe, pdiff, pdifft / 60, pdifft % 60)
 
diff --git a/lib/sectorbuilder/sectorbuilder_test.go b/lib/sectorbuilder/sectorbuilder_test.go
index e02368913..bb965c2bb 100644
--- a/lib/sectorbuilder/sectorbuilder_test.go
+++ b/lib/sectorbuilder/sectorbuilder_test.go
@@ -27,10 +27,23 @@ func TestSealAndVerify(t *testing.T) {
 		t.Fatalf("%+v", err)
 	}
 
-	sb, cleanup, err := sectorbuilder.TempSectorbuilder(sectorSize, datastore.NewMapDatastore())
+	ds := datastore.NewMapDatastore()
+
+	dir, err := ioutil.TempDir("", "sbtest")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	sb, err := sectorbuilder.TempSectorbuilderDir(dir, sectorSize, ds)
 	if err != nil {
 		t.Fatalf("%+v", err)
 	}
+	cleanup := func() {
+		sb.Destroy()
+		if err := os.RemoveAll(dir); err != nil {
+			t.Error(err)
+		}
+	}
 	defer cleanup()
 
 	dlen := sectorbuilder.UserBytesForSectorSize(sectorSize)
@@ -94,6 +107,26 @@ func TestSealAndVerify(t *testing.T) {
 	if !ok {
 		t.Fatal("bad post")
 	}
+
+	// Restart sectorbuilder, re-run post
+	sb.Destroy()
+	sb, err = sectorbuilder.TempSectorbuilderDir(dir, sectorSize, ds)
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+
+	postProof, err = sb.GeneratePoSt(ssi, cSeed, []uint64{})
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+
+	ok, err = sectorbuilder.VerifyPost(sb.SectorSize(), ssi, cSeed, postProof, []uint64{})
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+	if !ok {
+		t.Fatal("bad post")
+	}
 }
 
 func TestAcquireID(t *testing.T) {
diff --git a/storage/post.go b/storage/post.go
index 3d6ac56b3..0bcd66bb5 100644
--- a/storage/post.go
+++ b/storage/post.go
@@ -147,6 +147,10 @@ func (p *post) preparePost(ctx context.Context) error {
 	if err != nil {
 		return xerrors.Errorf("failed to get proving set for miner: %w", err)
 	}
+	if len(sset) == 0 {
+		log.Warn("empty proving set! (ts.H: %d)", p.ts.Height())
+	}
+
 	p.sset = sset
 
 	// Compute how many blocks back we have to look from the given tipset for the PoSt challenge
@@ -181,7 +185,7 @@ func (p *post) runPost(ctx context.Context) error {
 
 	log.Infow("running PoSt", "delayed-by",
 		int64(p.ts.Height())-(int64(p.ppe)-int64(build.PoStChallangeTime)),
-		"chain-random", p.r, "ppe", p.ppe, "height", p.ts.Height())
+		"chain-random", p.r, "ppe", p.ppe, "height", p.ts.Height(), "sectors", len(p.sset))
 
 	tsStart := time.Now()
 	var faults []uint64 // TODO
@@ -189,6 +193,9 @@ func (p *post) runPost(ctx context.Context) error {
 	var seed [32]byte
 	copy(seed[:], p.r)
 
+	vals := p.sortedSectorInfo()
+	log.Infof("SSI: %+v", vals.Values())
+
 	proof, err := p.m.sb.GeneratePoSt(p.sortedSectorInfo(), seed, faults)
 	if err != nil {
 		return xerrors.Errorf("running post failed: %w", err)
@@ -270,7 +277,7 @@ func (m *Miner) computePost(ppe uint64) func(ctx context.Context, ts *types.TipS
 			ts:  ts,
 		}).doPost(ctx)
 		if err != nil {
-			return err
+			return xerrors.Errorf("doPost: %w", err)
 		}
 
 		m.scheduleNextPost(ppe + build.ProvingPeriodDuration)