diff --git a/internal/appdir/appdir.go b/internal/appdir/appdir.go
index fa2cd076..ab036140 100644
--- a/internal/appdir/appdir.go
+++ b/internal/appdir/appdir.go
@@ -20,10 +20,14 @@
 // keychain, the folders the OS reads for autostart and link handling, and
 // temporary folders.
 //
-// A data folder in a folder every app shares (/Applications on a Mac) is
-// not taken for magpie's own while magpie's installed folder holds its
-// files (#989): a "data" folder there is as likely another app's, and
-// taking it showed a user who had never asked for portable an empty magpie.
+// A data folder in a folder every app or download shares (/Applications on
+// a Mac; the home folder, Downloads, Desktop and Documents everywhere) is
+// taken for magpie's own only when it already holds magpie's files and the
+// installed folder doesn't, or with a ".portable" marker: a "data" folder
+// there is as likely another app's or the user's own. Taking one showed a
+// user who had never asked for portable an empty magpie (#989), and wrote
+// magpie's files into a Downloads\data folder a Windows user's archiver
+// empties, so a provider just added was gone (tangle778 on X).
 //
 // The decision is made once, from the executable as it was when magpie
 // started: an update moving the running copy aside (into .magpie-update on
@@ -65,7 +69,7 @@ func Portable() string {
 		portable = Resolve(exe)
 		if portable == "" {
 			if data := Passed(exe); data != "" {
-				log.Printf("appdir: %s is beside magpie but not taken for its portable data: it is in a folder every app shares, and %s has magpie's files (#989)", data, installed())
+				log.Printf("appdir: %s is beside magpie but not taken for its portable data: it is in a shared folder and %s has magpie's files too; a .portable file beside magpie makes it portable", data, installed())
 			}
 		}
 	})
@@ -93,61 +97,75 @@ func Resolve(exe string) string {
 	if fi, err := os.Stat(filepath.Join(base, MarkerName)); err == nil && !fi.IsDir() {
 		return absolute(data)
 	}
-	if fi, err := os.Stat(data); err == nil && fi.IsDir() && !shared(base) {
+	if fi, err := os.Stat(data); err == nil && fi.IsDir() && !shared(base, data) {
 		return absolute(data)
 	}
 	return ""
 }
 
-// Passed is the data folder beside a magpie run from exe that Resolve
-// doesn't take for its own because it is in a folder every app shares
-// while the installed folder has magpie's files, or "".
+// Passed is the data folder beside a magpie run from exe that holds
+// magpie's files but that Resolve doesn't take for its own, because it is
+// in a shared folder while the installed folder has magpie's files too, or
+// "". A data folder holding none of them is someone else's and isn't named.
 func Passed(exe string) string {
 	if real, err := filepath.EvalSymlinks(exe); err == nil {
 		exe = real
 	}
 	base := Beside(exe)
 	data := filepath.Join(base, DataName)
-	if fi, err := os.Stat(data); err == nil && fi.IsDir() && Resolve(exe) == "" {
+	if fi, err := os.Stat(data); err == nil && fi.IsDir() && hasFiles(data) && Resolve(exe) == "" {
 		return absolute(data)
 	}
 	return ""
 }
 
-// shared says whether a data folder in dir can't be taken for magpie's:
-// dir is a folder every app shares (/Applications or ~/Applications on a
-// Mac), where a folder named data is as likely another app's, and the
-// installed folder holds magpie's files. One who keeps magpie portable
-// there never ran it installed, and keeps it portable; a ".portable"
-// marker beside it makes it portable whatever is installed.
-func shared(dir string) bool {
+// shared says whether the data folder in dir can't be taken for magpie's:
+// dir is a folder every app or download shares, where a folder named data
+// is as likely another app's or the user's own, and either data holds none
+// of magpie's files or the installed folder holds them too. One who keeps
+// magpie portable there has its files in data and never ran it installed,
+// and keeps it portable; a ".portable" marker beside it makes it portable
+// whatever is there.
+func shared(dir, data string) bool {
 	if !sharedFolder(dir) {
 		return false
 	}
-	in := installed()
-	if in == "" {
-		return false
+	if !hasFiles(data) {
+		return true
 	}
+	in := installed()
+	return in != "" && hasFiles(in)
+}
+
+// hasFiles says whether dir holds magpie's own files.
+func hasFiles(dir string) bool {
 	for _, f := range []string{"providers.json", "logins.json", "settings.json"} {
-		if fi, err := os.Stat(filepath.Join(in, f)); err == nil && !fi.IsDir() {
+		if fi, err := os.Stat(filepath.Join(dir, f)); err == nil && !fi.IsDir() {
 			return true
 		}
 	}
 	return false
 }
 
-// sharedFolder says whether dir is a folder every app shares; tests change
-// it.
+// sharedFolder says whether dir is a folder every app or download shares:
+// /Applications and ~/Applications on a Mac, and the home folder, its
+// Downloads, Desktop and Documents everywhere. Tests change it.
 var sharedFolder = func(dir string) bool {
-	if runtime.GOOS != "darwin" {
-		return false
+	var dirs []string
+	if runtime.GOOS == "darwin" {
+		dirs = append(dirs, "/Applications")
 	}
-	dirs := []string{"/Applications"}
 	if h, err := Home(); err == nil {
-		dirs = append(dirs, filepath.Join(h, "Applications"))
+		dirs = append(dirs, h)
+		for _, d := range []string{"Downloads", "Desktop", "Documents"} {
+			dirs = append(dirs, filepath.Join(h, d))
+		}
+		if runtime.GOOS == "darwin" {
+			dirs = append(dirs, filepath.Join(h, "Applications"))
+		}
 	}
 	for _, d := range dirs {
-		if strings.EqualFold(filepath.Clean(dir), d) {
+		if strings.EqualFold(filepath.Clean(dir), filepath.Clean(d)) {
 			return true
 		}
 	}
diff --git a/internal/appdir/appdir_test.go b/internal/appdir/appdir_test.go
index 71772588..1a435af1 100644
--- a/internal/appdir/appdir_test.go
+++ b/internal/appdir/appdir_test.go
@@ -182,6 +182,12 @@ func TestResolveSharedFolder(t *testing.T) {
 	mkdir(t, filepath.Join(data, "nodes"))
 	touch(t, filepath.Join(data, "install-id"))
 
+	// another app's data folder, nothing installed: not taken
+	if got := Resolve(exe); got != "" {
+		t.Errorf("no magpie files in data: %q, want installed", got)
+	}
+	touch(t, filepath.Join(data, "settings.json"))
+
 	// nothing installed: one who keeps magpie portable there
 	if got := Resolve(exe); got != data {
 		t.Errorf("nothing installed: %q, want %q", got, data)
@@ -216,6 +222,59 @@ func TestResolveSharedFolder(t *testing.T) {
 	}
 }
 
+// tangle778 on X: magpie.exe run from Downloads beside a data folder the
+// user's archiver empties wrote its providers there and lost them. A data
+// folder in Downloads holding none of magpie's files isn't its portable
+// data; one that does is, and .portable always makes it portable.
+func TestResolveDownloads(t *testing.T) {
+	t.Setenv("APPIMAGE", "")
+	r := root(t)
+	h := filepath.Join(r, "home")
+	t.Setenv("HOME", h)
+	t.Setenv("USERPROFILE", h)
+	t.Setenv("XDG_CONFIG_HOME", "")
+	dl := filepath.Join(h, "Downloads")
+	exe := touch(t, filepath.Join(dl, "magpie.exe"))
+	data := filepath.Join(dl, "data")
+	touch(t, filepath.Join(data, "report.json"))
+
+	if got := Resolve(exe); got != "" {
+		t.Errorf("user's data folder: %q, want installed", got)
+	}
+	if got := Passed(exe); got != "" {
+		t.Errorf("user's data folder: Passed %q, want none", got)
+	}
+	touch(t, filepath.Join(data, "providers.json"))
+	if got := Resolve(exe); got != data {
+		t.Errorf("portable run before: %q, want %q", got, data)
+	}
+	touch(t, filepath.Join(h, ".config", "magpie", "logins.json"))
+	if got := Resolve(exe); got != "" {
+		t.Errorf("installed has files: %q, want installed", got)
+	}
+	if got := Passed(exe); got != data {
+		t.Errorf("Passed %q, want %q", got, data)
+	}
+	touch(t, filepath.Join(dl, ".portable"))
+	if got := Resolve(exe); got != data {
+		t.Errorf(".portable: %q, want %q", got, data)
+	}
+}
+
+func TestSharedFolders(t *testing.T) {
+	h, _ := Home()
+	for _, d := range []string{h, filepath.Join(h, "Downloads"), filepath.Join(h, "Downloads") + string(filepath.Separator), filepath.Join(h, "Desktop"), filepath.Join(h, "Documents")} {
+		if !sharedFolder(d) {
+			t.Errorf("%s not shared", d)
+		}
+	}
+	for _, d := range []string{filepath.Join(h, "Downloads", "magpie"), filepath.Join(h, "tools")} {
+		if sharedFolder(d) {
+			t.Errorf("%s shared", d)
+		}
+	}
+}
+
 func TestSharedFolderIsApplications(t *testing.T) {
 	if runtime.GOOS != "darwin" {
 		if sharedFolder("/Applications") {
@@ -229,7 +288,7 @@ func TestSharedFolderIsApplications(t *testing.T) {
 			t.Errorf("%s not shared", d)
 		}
 	}
-	for _, d := range []string{"/Volumes/USB", filepath.Join(h, "Downloads"), "/Applications/Utilities"} {
+	for _, d := range []string{"/Volumes/USB", "/Applications/Utilities"} {
 		if sharedFolder(d) {
 			t.Errorf("%s shared", d)
 		}