diff --git a/README.md b/README.md
index c0532c4..9b80fb5 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,7 @@ approach: download the real MSVC/WinSDK, wrap the compiler under Wine.
 - [Quick start](#quick-start)
 - [Commands](#commands)
 - [Invoking tools without PATH](#invoking-tools-without-path)
+- [Diagnosing problems (vintner doctor)](#diagnosing-problems-vintner-doctor)
 - [Building drivers (WDK)](#building-drivers-wdk)
 - [Building against D3DX9 (DirectX SDK)](#building-against-d3dx9-directx-sdk)
 - [Automated/scripted builds](#automatedscripted-builds)
@@ -46,9 +47,9 @@ depending on the name it's invoked as.
   then runs the real `.exe` under `wine`/`wine64`, and rewrites `z:\...`
   paths back to Unix paths in the output, so your build system's error
   parsing keeps working.
-- As `vintner`: it exposes the `download`, `install`, `env`, `version`
-  and `completion` subcommands below (short aliases: `dl`, `i`, `e`, `v`;
-  `help`/`h` prints usage).
+- As `vintner`: it exposes the `download`, `install`, `env`, `version`,
+  `doctor` and `completion` subcommands below (short aliases: `dl`, `i`,
+  `e`, `v`; `help`/`h` prints usage).
 
 ## Installation
 
@@ -113,6 +114,7 @@ vintner download (dl) --accept-license [--dest <dir>] [options]   fetch and unpa
 vintner install (i) [dir]                                         wire up wrappers for a downloaded MSVC
 vintner env (e) --bin <dir>/bin/<arch>                            print INCLUDE/LIB for native clang-cl/lld-link use
 vintner version (v)                                               print the version
+vintner doctor                                                    check wine/toolchain setup
 vintner help (h)                                                  print usage
 vintner completion bash|zsh                                       print a shell completion script
 ```
@@ -154,6 +156,20 @@ than one is installed), otherwise defaults to
 `~/.vintner/bin/<host-arch>`, the layout a plain `vintner download &&
 vintner install` with no `--dest` override produces.
 
+## Diagnosing problems (vintner doctor)
+
+```bash
+vintner doctor
+```
+
+Checks the things vintner actually needs at runtime — that `wine`/`wine64`
+is on `PATH` and actually runs, that `msitools`/`cabextract` are present,
+and that every installed `<dest>/bin/<arch>` toolchain (or the one
+`VINTNER_BIN` points at) has its MSVC/SDK/MSBuild directories in place —
+and prints a pass/fail checklist. Exits non-zero if anything failed.
+Useful before filing a bug, or after a `download`/`install` that seemed to
+finish but left tools failing in confusing ways.
+
 ## Building drivers (WDK)
 
 `--with-wdk` also fetches the Windows Driver Kit: headers, import libs,
diff --git a/cmd/vintner/completion.go b/cmd/vintner/completion.go
index 7a5e4b1..231e4b7 100644
--- a/cmd/vintner/completion.go
+++ b/cmd/vintner/completion.go
@@ -49,7 +49,7 @@ const downloadFlags = "--dest --cache --major --preview --manifest --accept-lice
 // plus every short alias) - unlike the wrapped-tool names, these really are
 // fixed enough to hand-maintain: adding one is rare and always touches
 // main.go's dispatch switch right next to this file anyway.
-const subcommandNames = "download dl install i env e version v help h completion"
+const subcommandNames = "download dl install i env e version v doctor help h completion"
 
 func bashCompletionScript() string {
 	return `# vintner bash completion - eval "$(vintner completion bash)"
@@ -104,6 +104,7 @@ _vintner() {
         'e:alias for env'
         'version:print the version'
         'v:alias for version'
+        'doctor:check wine/toolchain setup'
         'help:print usage'
         'h:alias for help'
         'completion:print a shell completion script'
diff --git a/cmd/vintner/doctor.go b/cmd/vintner/doctor.go
new file mode 100644
index 0000000..f597642
--- /dev/null
+++ b/cmd/vintner/doctor.go
@@ -0,0 +1,176 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"time"
+
+	"github.com/Cheviiot/vintner/internal/i18n"
+	"github.com/Cheviiot/vintner/internal/wineenv"
+)
+
+// runDoctor checks the pieces vintner actually needs at runtime - wine
+// itself, the optional extraction tools download needs, and every
+// installed <dest>/bin/<arch> toolchain's on-disk layout - and prints a
+// pass/fail checklist. The point is surfacing a broken setup as a short,
+// readable report instead of a wine-specific error buried deep inside a
+// build (see internal/wineenv.FindWine's own error, which this reuses).
+func runDoctor(args []string) int {
+	if len(args) > 0 && (args[0] == "-h" || args[0] == "--help") {
+		fmt.Fprintln(os.Stderr, i18n.T("doctor.usage"))
+		return 1
+	}
+
+	d := &doctorReport{}
+	d.checkWine()
+	d.checkExtractionTools()
+	d.checkToolchains()
+
+	if d.failed {
+		fmt.Println(i18n.T("doctor.summary_fail"))
+		return 1
+	}
+	fmt.Println(i18n.T("doctor.summary_ok"))
+	return 0
+}
+
+type doctorReport struct {
+	failed bool
+}
+
+func (d *doctorReport) ok(format string, args ...any) {
+	fmt.Printf("  [ok]   "+format+"\n", args...)
+}
+
+func (d *doctorReport) warn(format string, args ...any) {
+	fmt.Printf("  [warn] "+format+"\n", args...)
+}
+
+func (d *doctorReport) fail(format string, args ...any) {
+	fmt.Printf("  [FAIL] "+format+"\n", args...)
+	d.failed = true
+}
+
+func (d *doctorReport) checkWine() {
+	fmt.Println(i18n.T("doctor.section_wine"))
+
+	wineBin, err := wineenv.FindWine()
+	if err != nil {
+		d.fail("%s", err)
+		return
+	}
+	d.ok("found: %s", wineBin)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	out, err := exec.CommandContext(ctx, wineBin, "--version").Output()
+	if err != nil {
+		d.fail("%s --version failed: %v", wineBin, err)
+		return
+	}
+	d.ok("runs: %s", trimNewline(string(out)))
+}
+
+func (d *doctorReport) checkExtractionTools() {
+	fmt.Println(i18n.T("doctor.section_extract"))
+
+	if _, err := exec.LookPath("msiextract"); err != nil {
+		d.warn(i18n.T("doctor.msitools_missing"))
+	} else {
+		d.ok("msitools: found (needed by `vintner download`)")
+	}
+
+	if _, err := exec.LookPath("cabextract"); err != nil {
+		d.warn(i18n.T("doctor.cabextract_missing"))
+	} else {
+		d.ok("cabextract: found (needed by --with-wdk/--with-dxsdk)")
+	}
+}
+
+func (d *doctorReport) checkToolchains() {
+	fmt.Println(i18n.T("doctor.section_toolchain"))
+
+	if binDir := os.Getenv("VINTNER_BIN"); binDir != "" {
+		d.checkToolchainAt(binDir, "VINTNER_BIN="+binDir)
+		return
+	}
+
+	def, err := defaultToolchainDir()
+	if err != nil {
+		d.fail("%s", err)
+		return
+	}
+	destBin := filepath.Join(def, "bin")
+	archDirs := installedArchDirs(destBin)
+	if len(archDirs) == 0 {
+		d.fail(i18n.T("doctor.no_toolchain", destBin))
+		return
+	}
+	for _, arch := range archDirs {
+		d.checkToolchainAt(filepath.Join(destBin, arch), arch)
+	}
+}
+
+// installedArchDirs returns the subdirectories of destBin that carry their
+// own env.json, i.e. every architecture `vintner install` actually set up
+// (there can be more than one - e.g. x86 and x64 side by side).
+func installedArchDirs(destBin string) []string {
+	entries, err := os.ReadDir(destBin)
+	if err != nil {
+		return nil
+	}
+	var dirs []string
+	for _, e := range entries {
+		if !e.IsDir() {
+			continue
+		}
+		if _, err := os.Stat(filepath.Join(destBin, e.Name(), wineenv.ConfigFileName)); err == nil {
+			dirs = append(dirs, e.Name())
+		}
+	}
+	return dirs
+}
+
+func (d *doctorReport) checkToolchainAt(binDir, label string) {
+	cfg, err := wineenv.Load(binDir)
+	if err != nil {
+		d.fail("%s: %s", label, err)
+		return
+	}
+	baseUnix, err := wineenv.FindBaseUnix(binDir)
+	if err != nil {
+		d.fail("%s: %s", label, err)
+		return
+	}
+	d.ok("%s: MSVC %s, SDK %s, root %s", label, cfg.MSVCVer, cfg.SDKVer, baseUnix)
+
+	paths := wineenv.NewPaths(cfg, baseUnix)
+	for _, dir := range []struct{ name, path string }{
+		{"MSVC bin", paths.BinDir},
+		{"SDK bin", paths.SDKBinDir},
+		{"MSBuild bin", paths.MSBuildBinDir},
+	} {
+		if fi, err := os.Stat(dir.path); err != nil || !fi.IsDir() {
+			d.fail("%s: %s missing: %s", label, dir.name, dir.path)
+		} else {
+			d.ok("%s: %s: %s", label, dir.name, dir.path)
+		}
+	}
+
+	relay := filepath.Join(baseUnix, "bin", "toolrelay.exe")
+	if fi, err := os.Stat(relay); err != nil || fi.IsDir() {
+		d.warn("%s: toolrelay.exe not built (mt.exe's CMake exit-code translation won't apply; re-run `vintner install` to retry)", label)
+	} else {
+		d.ok("%s: toolrelay.exe: %s", label, relay)
+	}
+}
+
+func trimNewline(s string) string {
+	for len(s) > 0 && (s[len(s)-1] == '\n' || s[len(s)-1] == '\r') {
+		s = s[:len(s)-1]
+	}
+	return s
+}
diff --git a/cmd/vintner/doctor_test.go b/cmd/vintner/doctor_test.go
new file mode 100644
index 0000000..a23f3e8
--- /dev/null
+++ b/cmd/vintner/doctor_test.go
@@ -0,0 +1,83 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/Cheviiot/vintner/internal/wineenv"
+)
+
+func TestRunDoctorUsage(t *testing.T) {
+	for _, flag := range []string{"-h", "--help"} {
+		if code := runDoctor([]string{flag}); code != 1 {
+			t.Errorf("runDoctor([%q]) = %d, want 1", flag, code)
+		}
+	}
+}
+
+func TestDoctorReportOkWarnFail(t *testing.T) {
+	d := &doctorReport{}
+	d.ok("fine")
+	d.warn("meh")
+	if d.failed {
+		t.Fatal("ok/warn must not mark the report as failed")
+	}
+	d.fail("broken")
+	if !d.failed {
+		t.Fatal("fail must mark the report as failed")
+	}
+}
+
+func TestInstalledArchDirsFindsOnlyDirsWithEnvJSON(t *testing.T) {
+	destBin := t.TempDir()
+	for _, dir := range []string{"x64", "x86", "not-a-toolchain"} {
+		if err := os.MkdirAll(filepath.Join(destBin, dir), 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, dir := range []string{"x64", "x86"} {
+		if err := os.WriteFile(filepath.Join(destBin, dir, wineenv.ConfigFileName), []byte("{}"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	got := installedArchDirs(destBin)
+	want := map[string]bool{"x64": true, "x86": true}
+	if len(got) != len(want) {
+		t.Fatalf("installedArchDirs = %v, want exactly %v", got, want)
+	}
+	for _, arch := range got {
+		if !want[arch] {
+			t.Errorf("installedArchDirs returned unexpected entry %q", arch)
+		}
+	}
+}
+
+func TestInstalledArchDirsMissingDir(t *testing.T) {
+	if got := installedArchDirs(filepath.Join(t.TempDir(), "does-not-exist")); got != nil {
+		t.Errorf("installedArchDirs on a missing dir = %v, want nil", got)
+	}
+}
+
+func TestCheckToolchainAtMissingEnvJSON(t *testing.T) {
+	d := &doctorReport{}
+	d.checkToolchainAt(t.TempDir(), "test")
+	if !d.failed {
+		t.Error("checkToolchainAt against a dir with no env.json should fail the report")
+	}
+}
+
+func TestTrimNewline(t *testing.T) {
+	cases := map[string]string{
+		"wine-9.0\n":   "wine-9.0",
+		"wine-9.0\r\n": "wine-9.0",
+		"wine-9.0":     "wine-9.0",
+		"":             "",
+	}
+	for in, want := range cases {
+		if got := trimNewline(in); got != want {
+			t.Errorf("trimNewline(%q) = %q, want %q", in, got, want)
+		}
+	}
+}
diff --git a/cmd/vintner/main.go b/cmd/vintner/main.go
index 3587f70..2dee834 100644
--- a/cmd/vintner/main.go
+++ b/cmd/vintner/main.go
@@ -50,6 +50,8 @@ func runCLI(args []string) int {
 		return runEnv(args[1:])
 	case "completion":
 		return runCompletion(args[1:])
+	case "doctor":
+		return runDoctor(args[1:])
 	case "version", "v", "--version":
 		fmt.Println(versionString())
 		return 0
diff --git a/internal/i18n/i18n.go b/internal/i18n/i18n.go
index 0078299..f6fba76 100644
--- a/internal/i18n/i18n.go
+++ b/internal/i18n/i18n.go
@@ -73,6 +73,7 @@ Usage:
   vintner install (i) [dir]            wire up wrappers for a downloaded MSVC
   vintner env (e) --bin <dir/bin/arch> print INCLUDE/LIB for native clang-cl/lld-link use
   vintner version (v)                  print the version
+  vintner doctor                       check wine/toolchain setup
   vintner help (h)                     show this message
   vintner completion bash|zsh          print a shell completion script
 
@@ -98,6 +99,7 @@ not the default ~/.vintner/bin/<host-arch>):
   vintner install (i) [каталог]        настроить обёртки для скачанного MSVC
   vintner env (e) --bin <dir/bin/arch> вывести INCLUDE/LIB для clang-cl/lld-link напрямую
   vintner version (v)                  показать версию
+  vintner doctor                       проверить настройку wine/toolchain
   vintner help (h)                     показать эту справку
   vintner completion bash|zsh          вывести скрипт автодополнения для оболочки
 
@@ -188,4 +190,41 @@ not the default ~/.vintner/bin/<host-arch>):
 		EN: "Do you accept the license? Answer \"yes\" or \"no\": ",
 		RU: "Вы принимаете лицензию? Ответьте «yes» или «no»: ",
 	},
+
+	"doctor.usage": {
+		EN: "usage: vintner doctor",
+		RU: "использование: vintner doctor",
+	},
+	"doctor.section_wine": {
+		EN: "Wine:",
+		RU: "Wine:",
+	},
+	"doctor.section_extract": {
+		EN: "Extraction tools:",
+		RU: "Инструменты распаковки:",
+	},
+	"doctor.section_toolchain": {
+		EN: "Installed toolchain:",
+		RU: "Установленный набор инструментов:",
+	},
+	"doctor.msitools_missing": {
+		EN: "msitools: not found (install the msitools package - needed by `vintner download`)",
+		RU: "msitools: не найден (установите пакет msitools — нужен для `vintner download`)",
+	},
+	"doctor.cabextract_missing": {
+		EN: "cabextract: not found (install the cabextract package - only needed for --with-wdk/--with-dxsdk)",
+		RU: "cabextract: не найден (установите пакет cabextract — нужен только для --with-wdk/--with-dxsdk)",
+	},
+	"doctor.no_toolchain": {
+		EN: "no installed toolchain found under %s (run `vintner download --accept-license && vintner install` first, or set VINTNER_BIN)",
+		RU: "установленный набор инструментов не найден в %s (сначала выполните `vintner download --accept-license && vintner install`, либо задайте VINTNER_BIN)",
+	},
+	"doctor.summary_ok": {
+		EN: "\nAll checks passed.",
+		RU: "\nВсе проверки пройдены.",
+	},
+	"doctor.summary_fail": {
+		EN: "\nSome checks failed - see [FAIL] lines above.",
+		RU: "\nНекоторые проверки не пройдены — см. строки [FAIL] выше.",
+	},
 }