diff --git a/cmd/ctr/run_windows.go b/cmd/ctr/run_windows.go
index a54780916..8a430eb3e 100644
--- a/cmd/ctr/run_windows.go
+++ b/cmd/ctr/run_windows.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
-	"runtime"
 	"time"
 
 	"github.com/Sirupsen/logrus"
@@ -67,14 +66,10 @@ func spec(id string, config *ocispec.ImageConfig, context *cli.Context) *specs.S
 
 	return &specs.Spec{
 		Version: specs.Version,
-		Platform: specs.Platform{
-			OS:   runtime.GOOS,
-			Arch: runtime.GOARCH,
-		},
 		Root: specs.Root{
 			Readonly: context.Bool("readonly"),
 		},
-		Process: specs.Process{
+		Process: &specs.Process{
 			Args:     args,
 			Terminal: tty,
 			Cwd:      cwd,
@@ -82,7 +77,7 @@ func spec(id string, config *ocispec.ImageConfig, context *cli.Context) *specs.S
 			User: specs.User{
 				Username: config.User,
 			},
-			ConsoleSize: specs.Box{
+			ConsoleSize: &specs.Box{
 				Height: uint(w),
 				Width:  uint(h),
 			},
diff --git a/metrics/cgroups/blkio.go b/metrics/cgroups/blkio.go
index cd9ca2963..481ac3541 100644
--- a/metrics/cgroups/blkio.go
+++ b/metrics/cgroups/blkio.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/metrics/cgroups/cpu.go b/metrics/cgroups/cpu.go
index 79e8de7e8..d6ffee94a 100644
--- a/metrics/cgroups/cpu.go
+++ b/metrics/cgroups/cpu.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/metrics/cgroups/hugetlb.go b/metrics/cgroups/hugetlb.go
index 3540e1aa2..01c406d23 100644
--- a/metrics/cgroups/hugetlb.go
+++ b/metrics/cgroups/hugetlb.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/metrics/cgroups/memory.go b/metrics/cgroups/memory.go
index 6780b1168..e942efbdf 100644
--- a/metrics/cgroups/memory.go
+++ b/metrics/cgroups/memory.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/metrics/cgroups/metric.go b/metrics/cgroups/metric.go
index bc9d170b5..519e524f2 100644
--- a/metrics/cgroups/metric.go
+++ b/metrics/cgroups/metric.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/metrics/cgroups/metrics.go b/metrics/cgroups/metrics.go
index ed170b0b5..247db4614 100644
--- a/metrics/cgroups/metrics.go
+++ b/metrics/cgroups/metrics.go
@@ -1,7 +1,10 @@
+// +build linux
+
 package cgroups
 
 import (
 	"errors"
+	"fmt"
 	"strconv"
 	"sync"
 
@@ -43,6 +46,10 @@ type task struct {
 	cgroup    cgroups.Cgroup
 }
 
+func taskID(id, namespace string) string {
+	return fmt.Sprintf("%s-%s", id, namespace)
+}
+
 // Collector provides the ability to collect container stats and export
 // them in the prometheus format
 type Collector struct {
@@ -86,10 +93,10 @@ func (c *Collector) collect(id, namespace string, cg cgroups.Cgroup, ch chan<- p
 func (c *Collector) Add(id, namespace string, cg cgroups.Cgroup) error {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	if _, ok := c.cgroups[id+namespace]; ok {
+	if _, ok := c.cgroups[taskID(id, namespace)]; ok {
 		return ErrAlreadyCollected
 	}
-	c.cgroups[id+namespace] = &task{
+	c.cgroups[taskID(id, namespace)] = &task{
 		id:        id,
 		namespace: namespace,
 		cgroup:    cg,
@@ -102,7 +109,7 @@ func (c *Collector) Add(id, namespace string, cg cgroups.Cgroup) error {
 func (c *Collector) Get(id, namespace string) (cgroups.Cgroup, error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	t, ok := c.cgroups[id+namespace]
+	t, ok := c.cgroups[taskID(id, namespace)]
 	if !ok {
 		return nil, ErrCgroupNotExists
 	}
@@ -113,7 +120,7 @@ func (c *Collector) Get(id, namespace string) (cgroups.Cgroup, error) {
 func (c *Collector) Remove(id, namespace string) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	delete(c.cgroups, id+namespace)
+	delete(c.cgroups, taskID(id, namespace))
 }
 
 func blkioValues(l []cgroups.BlkioEntry) []value {
diff --git a/metrics/cgroups/oom.go b/metrics/cgroups/oom.go
index 493dd0be2..f38dd3e54 100644
--- a/metrics/cgroups/oom.go
+++ b/metrics/cgroups/oom.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/metrics/cgroups/pids.go b/metrics/cgroups/pids.go
index 3cb775404..35e7d4fd8 100644
--- a/metrics/cgroups/pids.go
+++ b/metrics/cgroups/pids.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package cgroups
 
 import (
diff --git a/spec_windows.go b/spec_windows.go
index 7f0bae0cb..e39e34895 100644
--- a/spec_windows.go
+++ b/spec_windows.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"runtime"
 
 	"github.com/containerd/containerd/api/services/containers/v1"
 	"github.com/containerd/containerd/images"
@@ -18,13 +17,9 @@ const pipeRoot = `\\.\pipe`
 func createDefaultSpec() (*specs.Spec, error) {
 	return &specs.Spec{
 		Version: specs.Version,
-		Platform: specs.Platform{
-			OS:   runtime.GOOS,
-			Arch: runtime.GOARCH,
-		},
-		Root: specs.Root{},
-		Process: specs.Process{
-			ConsoleSize: specs.Box{
+		Root:    specs.Root{},
+		Process: &specs.Process{
+			ConsoleSize: &specs.Box{
 				Width:  80,
 				Height: 20,
 			},
diff --git a/windows/container.go b/windows/container.go
index 7102fb7c7..3e60bdb88 100644
--- a/windows/container.go
+++ b/windows/container.go
@@ -142,7 +142,7 @@ func (c *container) Exec(ctx context.Context, opts plugin.ExecOpts) (plugin.Proc
 		return nil, errors.Wrap(err, "failed to unmarshal oci spec")
 	}
 
-	p, err := c.ctr.AddProcess(ctx, procSpec, pio)
+	p, err := c.ctr.AddProcess(ctx, &procSpec, pio)
 	if err != nil {
 		return nil, err
 	}
diff --git a/windows/hcs/hcs.go b/windows/hcs/hcs.go
index 41fa3caef..d1016a28a 100644
--- a/windows/hcs/hcs.go
+++ b/windows/hcs/hcs.go
@@ -303,7 +303,7 @@ func (c *Container) GetConfiguration() Configuration {
 	return c.conf
 }
 
-func (c *Container) AddProcess(ctx context.Context, spec specs.Process, io *IO) (*Process, error) {
+func (c *Container) AddProcess(ctx context.Context, spec *specs.Process, io *IO) (*Process, error) {
 	if len(c.processes) == 0 {
 		return nil, errors.New("container not started")
 	}
@@ -311,7 +311,7 @@ func (c *Container) AddProcess(ctx context.Context, spec specs.Process, io *IO)
 	return c.addProcess(ctx, spec, io)
 }
 
-func (c *Container) addProcess(ctx context.Context, spec specs.Process, pio *IO) (*Process, error) {
+func (c *Container) addProcess(ctx context.Context, spec *specs.Process, pio *IO) (*Process, error) {
 	// If we don't have a process yet, reused the container pid
 	var pid uint32
 	if len(c.processes) == 0 {