diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index daffda30c1..a9aa9f61fe 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -390,7 +390,7 @@ func makeDefaultExtra() []byte {
 }
 
 func run(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 	if ctx.GlobalBool(utils.OlympicFlag.Name) {
 		utils.InitOlympic()
 	}
@@ -409,7 +409,7 @@ func run(ctx *cli.Context) {
 }
 
 func attach(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	var client comms.EthereumClient
 	var err error
@@ -441,7 +441,7 @@ func attach(ctx *cli.Context) {
 }
 
 func console(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	cfg := utils.MakeEthConfig(ClientIdentifier, nodeNameVersion, ctx)
 	cfg.ExtraData = makeExtra(ctx)
@@ -475,7 +475,7 @@ func console(ctx *cli.Context) {
 }
 
 func execJSFiles(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	cfg := utils.MakeEthConfig(ClientIdentifier, nodeNameVersion, ctx)
 	ethereum, err := eth.New(cfg)
@@ -502,7 +502,7 @@ func execJSFiles(ctx *cli.Context) {
 }
 
 func unlockAccount(ctx *cli.Context, am *accounts.Manager, addr string, i int) (addrHex, auth string) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	var err error
 	addrHex, err = utils.ParamToAddress(addr, am)
@@ -527,7 +527,7 @@ func unlockAccount(ctx *cli.Context, am *accounts.Manager, addr string, i int) (
 }
 
 func blockRecovery(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	arg := ctx.Args().First()
 	if len(ctx.Args()) < 1 && len(arg) > 0 {
@@ -593,7 +593,7 @@ func startEth(ctx *cli.Context, eth *eth.Ethereum) {
 }
 
 func accountList(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	am := utils.MakeAccountManager(ctx)
 	accts, err := am.Accounts()
@@ -643,7 +643,7 @@ func getPassPhrase(ctx *cli.Context, desc string, confirmation bool, i int) (pas
 }
 
 func accountCreate(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	am := utils.MakeAccountManager(ctx)
 	passphrase := getPassPhrase(ctx, "Your new account is locked with a password. Please give a password. Do not forget this password.", true, 0)
@@ -655,7 +655,7 @@ func accountCreate(ctx *cli.Context) {
 }
 
 func accountUpdate(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	am := utils.MakeAccountManager(ctx)
 	arg := ctx.Args().First()
@@ -672,7 +672,7 @@ func accountUpdate(ctx *cli.Context) {
 }
 
 func importWallet(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	keyfile := ctx.Args().First()
 	if len(keyfile) == 0 {
@@ -694,7 +694,7 @@ func importWallet(ctx *cli.Context) {
 }
 
 func accountImport(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	keyfile := ctx.Args().First()
 	if len(keyfile) == 0 {
@@ -710,7 +710,7 @@ func accountImport(ctx *cli.Context) {
 }
 
 func makedag(ctx *cli.Context) {
-	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
+	utils.CheckLegalese(utils.MustDataDir(ctx))
 
 	args := ctx.Args()
 	wrongArgs := func() {
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index b45ef0af2b..ad474f17d1 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -416,7 +416,7 @@ func MakeEthConfig(clientID, version string, ctx *cli.Context) *eth.Config {
 
 	cfg := &eth.Config{
 		Name:                    common.MakeName(clientID, version),
-		DataDir:                 ctx.GlobalString(DataDirFlag.Name),
+		DataDir:                 MustDataDir(ctx),
 		GenesisNonce:            ctx.GlobalInt(GenesisNonceFlag.Name),
 		GenesisFile:             ctx.GlobalString(GenesisFileFlag.Name),
 		BlockChainVersion:       ctx.GlobalInt(BlockchainVersionFlag.Name),
@@ -509,7 +509,7 @@ func SetupEth(ctx *cli.Context) {
 
 // MakeChain creates a chain manager from set command line flags.
 func MakeChain(ctx *cli.Context) (chain *core.ChainManager, chainDb ethdb.Database) {
-	datadir := ctx.GlobalString(DataDirFlag.Name)
+	datadir := MustDataDir(ctx)
 	cache := ctx.GlobalInt(CacheFlag.Name)
 
 	var err error
@@ -539,11 +539,21 @@ func MakeChain(ctx *cli.Context) (chain *core.ChainManager, chainDb ethdb.Databa
 
 // MakeChain creates an account manager from set command line flags.
 func MakeAccountManager(ctx *cli.Context) *accounts.Manager {
-	dataDir := ctx.GlobalString(DataDirFlag.Name)
+	dataDir := MustDataDir(ctx)
 	ks := crypto.NewKeyStorePassphrase(filepath.Join(dataDir, "keystore"))
 	return accounts.NewManager(ks)
 }
 
+// MustDataDir retrieves the currently requested data directory, terminating if
+// none (or the empty string) is specified.
+func MustDataDir(ctx *cli.Context) string {
+	if path := ctx.GlobalString(DataDirFlag.Name); path != "" {
+		return path
+	}
+	Fatalf("Cannot determine default data directory, please set manually (--datadir)")
+	return ""
+}
+
 func IpcSocketPath(ctx *cli.Context) (ipcpath string) {
 	if runtime.GOOS == "windows" {
 		ipcpath = common.DefaultIpcPath()
diff --git a/common/path.go b/common/path.go
index 8b3c7d14b8..1253c424ca 100644
--- a/common/path.go
+++ b/common/path.go
@@ -100,14 +100,24 @@ func DefaultAssetPath() string {
 }
 
 func DefaultDataDir() string {
-	usr, _ := user.Current()
-	if runtime.GOOS == "darwin" {
-		return filepath.Join(usr.HomeDir, "Library", "Ethereum")
-	} else if runtime.GOOS == "windows" {
-		return filepath.Join(usr.HomeDir, "AppData", "Roaming", "Ethereum")
+	// Try to place the data folder in the user's home dir
+	var home string
+	if usr, err := user.Current(); err == nil {
+		home = usr.HomeDir
 	} else {
-		return filepath.Join(usr.HomeDir, ".ethereum")
+		home = os.Getenv("HOME")
 	}
+	if home != "" {
+		if runtime.GOOS == "darwin" {
+			return filepath.Join(home, "Library", "Ethereum")
+		} else if runtime.GOOS == "windows" {
+			return filepath.Join(home, "AppData", "Roaming", "Ethereum")
+		} else {
+			return filepath.Join(home, ".ethereum")
+		}
+	}
+	// As we cannot guess a stable location, return empty and handle later
+	return ""
 }
 
 func DefaultIpcPath() string {