diff --git a/backend/union/entry.go b/backend/union/entry.go
index 2cd16c5f0..6b6a84b41 100644
--- a/backend/union/entry.go
+++ b/backend/union/entry.go
@@ -1,165 +1,170 @@
-package union
-
-import (
-	"bufio"
-	"context"
-	"io"
-	"sync"
-	"time"
-
-	"github.com/pkg/errors"
-	"github.com/rclone/rclone/backend/union/upstream"
-	"github.com/rclone/rclone/fs"
-)
-
-// Object describes a union Object
-//
-// This is a wrapped object which returns the Union Fs as its parent
-type Object struct {
-	*upstream.Object
-	fs *Fs // what this object is part of
-	co []upstream.Entry
-}
-
-// Directory describes a union Directory
-//
-// This is a wrapped object contains all candidates
-type Directory struct {
-	*upstream.Directory
-	cd []upstream.Entry
-}
-
-type entry interface {
-	upstream.Entry
-	candidates() []upstream.Entry
-}
-
-// UnWrap returns the Object that this Object is wrapping or
-// nil if it isn't wrapping anything
-func (o *Object) UnWrap() *upstream.Object {
-	return o.Object
-}
-
-// Fs returns the union Fs as the parent
-func (o *Object) Fs() fs.Info {
-	return o.fs
-}
-
-func (o *Object) candidates() []upstream.Entry {
-	return o.co
-}
-
-func (d *Directory) candidates() []upstream.Entry {
-	return d.cd
-}
-
-// Update in to the object with the modTime given of the given size
-//
-// When called from outside a Fs by rclone, src.Size() will always be >= 0.
-// But for unknown-sized objects (indicated by src.Size() == -1), Upload should either
-// return an error or update the object properly (rather than e.g. calling panic).
-func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) error {
-	f := o.Fs().(*Fs)
-	entries, err := f.actionEntries(o.candidates()...)
-	if err != nil {
-		return err
-	}
-	if len(entries) == 1 {
-		obj := entries[0].(*upstream.Object)
-		return obj.Update(ctx, in, src, options...)
-	}
-	// Get multiple reader
-	readers := make([]io.Reader, len(entries))
-	writers := make([]io.Writer, len(entries))
-	errs := Errors(make([]error, len(entries)+1))
-	for i := range entries {
-		r, w := io.Pipe()
-		bw := bufio.NewWriter(w)
-		readers[i], writers[i] = r, bw
-		defer w.Close()
-	}
-	go func() {
-		mw := io.MultiWriter(writers...)
-		es := make([]error, len(writers)+1)
-		_, es[len(es)-1] = io.Copy(mw, in)
-		for i, bw := range writers {
-			es[i] = bw.(*bufio.Writer).Flush()
-		}
-		errs[len(entries)] = Errors(es).Err()
-	}()
-	// Multi-threading
-	multithread(len(entries), func(i int) {
-		if o, ok := entries[i].(*upstream.Object); ok {
-			err := o.Update(ctx, readers[i], src, options...)
-			errs[i] = errors.Wrap(err, o.UpstreamFs().Name())
-		} else {
-			errs[i] = fs.ErrorNotAFile
-		}
-	})
-	return errs.Err()
-}
-
-// Remove candidate objects selected by ACTION policy
-func (o *Object) Remove(ctx context.Context) error {
-	f := o.Fs().(*Fs)
-	entries, err := f.actionEntries(o.candidates()...)
-	if err != nil {
-		return err
-	}
-	errs := Errors(make([]error, len(entries)))
-	multithread(len(entries), func(i int) {
-		if o, ok := entries[i].(*upstream.Object); ok {
-			err := o.Remove(ctx)
-			errs[i] = errors.Wrap(err, o.UpstreamFs().Name())
-		} else {
-			errs[i] = fs.ErrorNotAFile
-		}
-	})
-	return errs.Err()
-}
-
-// SetModTime sets the metadata on the object to set the modification date
-func (o *Object) SetModTime(ctx context.Context, t time.Time) error {
-	f := o.Fs().(*Fs)
-	entries, err := f.actionEntries(o.candidates()...)
-	if err != nil {
-		return err
-	}
-	var wg sync.WaitGroup
-	errs := Errors(make([]error, len(entries)))
-	multithread(len(entries), func(i int) {
-		if o, ok := entries[i].(*upstream.Object); ok {
-			err := o.SetModTime(ctx, t)
-			errs[i] = errors.Wrap(err, o.UpstreamFs().Name())
-		} else {
-			errs[i] = fs.ErrorNotAFile
-		}
-	})
-	wg.Wait()
-	return errs.Err()
-}
-
-// ModTime returns the modification date of the directory
-// It returns the latest ModTime of all candidates
-func (d *Directory) ModTime(ctx context.Context) (t time.Time) {
-	entries := d.candidates()
-	times := make([]time.Time, len(entries))
-	multithread(len(entries), func(i int) {
-		times[i] = entries[i].ModTime(ctx)
-	})
-	for _, ti := range times {
-		if t.Before(ti) {
-			t = ti
-		}
-	}
-	return t
-}
-
-// Size returns the size of the directory
-// It returns the sum of all candidates
-func (d *Directory) Size() (s int64) {
-	for _, e := range d.candidates() {
-		s += e.Size()
-	}
-	return s
-}
+package union
+
+import (
+	"bufio"
+	"context"
+	"io"
+	"sync"
+	"time"
+
+	"github.com/pkg/errors"
+	"github.com/rclone/rclone/backend/union/upstream"
+	"github.com/rclone/rclone/fs"
+)
+
+// Object describes a union Object
+//
+// This is a wrapped object which returns the Union Fs as its parent
+type Object struct {
+	*upstream.Object
+	fs *Fs // what this object is part of
+	co []upstream.Entry
+}
+
+// Directory describes a union Directory
+//
+// This is a wrapped object contains all candidates
+type Directory struct {
+	*upstream.Directory
+	cd []upstream.Entry
+}
+
+type entry interface {
+	upstream.Entry
+	candidates() []upstream.Entry
+}
+
+// UnWrap returns the Object that this Object is wrapping or
+// nil if it isn't wrapping anything
+func (o *Object) UnWrap() *upstream.Object {
+	return o.Object
+}
+
+// Fs returns the union Fs as the parent
+func (o *Object) Fs() fs.Info {
+	return o.fs
+}
+
+func (o *Object) candidates() []upstream.Entry {
+	return o.co
+}
+
+func (d *Directory) candidates() []upstream.Entry {
+	return d.cd
+}
+
+// Update in to the object with the modTime given of the given size
+//
+// When called from outside a Fs by rclone, src.Size() will always be >= 0.
+// But for unknown-sized objects (indicated by src.Size() == -1), Upload should either
+// return an error or update the object properly (rather than e.g. calling panic).
+func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) error {
+	f := o.Fs().(*Fs)
+	entries, err := f.actionEntries(o.candidates()...)
+	if err != nil {
+		return err
+	}
+	if len(entries) == 1 {
+		obj := entries[0].(*upstream.Object)
+		return obj.Update(ctx, in, src, options...)
+	}
+	// Get multiple reader
+	readers := make([]io.Reader, len(entries))
+	writers := make([]io.Writer, len(entries))
+	errs := Errors(make([]error, len(entries)+1))
+	for i := range entries {
+		r, w := io.Pipe()
+		bw := bufio.NewWriter(w)
+		readers[i], writers[i] = r, bw
+		defer func() {
+			err := w.Close()
+			if err != nil {
+				panic(err)
+			}
+		}()
+	}
+	go func() {
+		mw := io.MultiWriter(writers...)
+		es := make([]error, len(writers)+1)
+		_, es[len(es)-1] = io.Copy(mw, in)
+		for i, bw := range writers {
+			es[i] = bw.(*bufio.Writer).Flush()
+		}
+		errs[len(entries)] = Errors(es).Err()
+	}()
+	// Multi-threading
+	multithread(len(entries), func(i int) {
+		if o, ok := entries[i].(*upstream.Object); ok {
+			err := o.Update(ctx, readers[i], src, options...)
+			errs[i] = errors.Wrap(err, o.UpstreamFs().Name())
+		} else {
+			errs[i] = fs.ErrorNotAFile
+		}
+	})
+	return errs.Err()
+}
+
+// Remove candidate objects selected by ACTION policy
+func (o *Object) Remove(ctx context.Context) error {
+	f := o.Fs().(*Fs)
+	entries, err := f.actionEntries(o.candidates()...)
+	if err != nil {
+		return err
+	}
+	errs := Errors(make([]error, len(entries)))
+	multithread(len(entries), func(i int) {
+		if o, ok := entries[i].(*upstream.Object); ok {
+			err := o.Remove(ctx)
+			errs[i] = errors.Wrap(err, o.UpstreamFs().Name())
+		} else {
+			errs[i] = fs.ErrorNotAFile
+		}
+	})
+	return errs.Err()
+}
+
+// SetModTime sets the metadata on the object to set the modification date
+func (o *Object) SetModTime(ctx context.Context, t time.Time) error {
+	f := o.Fs().(*Fs)
+	entries, err := f.actionEntries(o.candidates()...)
+	if err != nil {
+		return err
+	}
+	var wg sync.WaitGroup
+	errs := Errors(make([]error, len(entries)))
+	multithread(len(entries), func(i int) {
+		if o, ok := entries[i].(*upstream.Object); ok {
+			err := o.SetModTime(ctx, t)
+			errs[i] = errors.Wrap(err, o.UpstreamFs().Name())
+		} else {
+			errs[i] = fs.ErrorNotAFile
+		}
+	})
+	wg.Wait()
+	return errs.Err()
+}
+
+// ModTime returns the modification date of the directory
+// It returns the latest ModTime of all candidates
+func (d *Directory) ModTime(ctx context.Context) (t time.Time) {
+	entries := d.candidates()
+	times := make([]time.Time, len(entries))
+	multithread(len(entries), func(i int) {
+		times[i] = entries[i].ModTime(ctx)
+	})
+	for _, ti := range times {
+		if t.Before(ti) {
+			t = ti
+		}
+	}
+	return t
+}
+
+// Size returns the size of the directory
+// It returns the sum of all candidates
+func (d *Directory) Size() (s int64) {
+	for _, e := range d.candidates() {
+		s += e.Size()
+	}
+	return s
+}
diff --git a/backend/union/upstream/upstream.go b/backend/union/upstream/upstream.go
index 39581c3e7..e6f73a09c 100644
--- a/backend/union/upstream/upstream.go
+++ b/backend/union/upstream/upstream.go
@@ -292,7 +292,9 @@ func (f *Fs) updateUsage() error {
 		return f.updateUsageCore(false)
 	}
 	if atomic.CompareAndSwapUint32(&f.cacheState, normal, updating) {
-		go f.updateUsageCore(true)
+		go func() {
+			_ = f.updateUsageCore(true)
+		}()
 	}
 	return nil
 }