diff --git a/server/auth.go b/server/auth.go
index cc82845c8..2aaa93e63 100644
--- a/server/auth.go
+++ b/server/auth.go
@@ -159,7 +159,6 @@ func createAdminUser(ctx context.Context, ds model.DataStore, username, password
 	}
 	err := ds.User(ctx).Put(&initialUser)
 	if err != nil {
-		// Log the username only: initialUser carries the password in clear text
 		log.Error(ctx, "Could not create initial user", "user", initialUser.UserName, err)
 		return fmt.Errorf("creating initial user: %w", err)
 	}
diff --git a/server/auth_test.go b/server/auth_test.go
index 9fdd84d06..abe144a12 100644
--- a/server/auth_test.go
+++ b/server/auth_test.go
@@ -76,8 +76,6 @@ var _ = Describe("Auth", func() {
 			})
 		})
 
-		// createAdminUser used to swallow the Put error and return nil, so a failure
-		// fell through to doLogin and surfaced as a misleading 401.
 		Describe("createAdmin when the user cannot be stored", func() {
 			It("responds 500 rather than falling through to login", func() {
 				failing := dsWithFailingPut(errors.New("db is down"))
diff --git a/server/initial_setup.go b/server/initial_setup.go
index f033d4a51..e75220abe 100644
--- a/server/initial_setup.go
+++ b/server/initial_setup.go
@@ -16,7 +16,7 @@ import (
 
 func initialSetup(ds model.DataStore) {
 	ctx := context.TODO()
-	_ = ds.WithTx(func(tx model.DataStore) error {
+	err := ds.WithTx(func(tx model.DataStore) error {
 		if err := tx.Library(ctx).StoreMusicFolder(); err != nil {
 			return err
 		}
@@ -36,6 +36,9 @@ func initialSetup(ds model.DataStore) {
 		err = properties.Put(consts.InitialSetupFlagKey, time.Now().String())
 		return err
 	}, "initial setup")
+	if err != nil {
+		log.Fatal("Error running initial setup", err)
+	}
 }
 
 // If the Dev Admin user is not present, create it
@@ -43,7 +46,7 @@ func createInitialAdminUser(ds model.DataStore, initialPassword string) error {
 	users := ds.User(context.TODO())
 	c, err := users.CountAll(model.QueryOptions{Filters: squirrel.Eq{"user_name": consts.DevInitialUserName}})
 	if err != nil {
-		panic(fmt.Sprintf("Could not access User table: %s", err))
+		return fmt.Errorf("could not access User table: %w", err)
 	}
 	if c == 0 {
 		newID := id.NewRandom()
@@ -57,14 +60,8 @@ func createInitialAdminUser(ds model.DataStore, initialPassword string) error {
 			NewPassword: initialPassword,
 			IsAdmin:     true,
 		}
-		// The Put error used to be assigned to a shadowed err and dropped, so a
-		// failure was reported as success and initialSetup went on to commit the
-		// "setup complete" flag — leaving no admin user, and skipping setup on
-		// every later boot.
 		if err := users.Put(&initialUser); err != nil {
-			// Log the username rather than the whole struct, as everywhere else
-			log.Error("Could not create initial admin user", "user", consts.DevInitialUserName, err)
-			return err
+			return fmt.Errorf("could not create initial admin user: %w", err)
 		}
 	}
 	return nil
diff --git a/server/initial_setup_test.go b/server/initial_setup_test.go
index b6d97d178..0ce8a39fa 100644
--- a/server/initial_setup_test.go
+++ b/server/initial_setup_test.go
@@ -10,8 +10,6 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-// failingPutUserRepo counts users normally but fails to store them, to exercise the
-// error path of the initial user creation.
 type failingPutUserRepo struct {
 	model.UserRepository
 	err error
@@ -47,11 +45,15 @@ var _ = Describe("initial_setup", func() {
 			Expect(ur.CountAll()).To(Equal(int64(1)))
 		})
 
-		// The error was assigned to a shadowed err and dropped, so the caller saw
-		// success and went on to commit the "setup complete" flag.
 		It("returns the error when the user cannot be stored", func() {
 			boom := errors.New("db is down")
 			Expect(createInitialAdminUser(dsWithFailingPut(boom), "pass123")).To(MatchError(boom))
 		})
+
+		It("returns the error when the user table cannot be read", func() {
+			boom := errors.New("db is down")
+			ds = &tests.MockDataStore{MockedUser: &tests.MockedUserRepo{Error: boom}}
+			Expect(createInitialAdminUser(ds, "pass123")).To(MatchError(boom))
+		})
 	})
 })
diff --git a/server/nativeapi/delete_many_response_test.go b/server/nativeapi/delete_many_response_test.go
index 9517d3b47..7d911d6cd 100644
--- a/server/nativeapi/delete_many_response_test.go
+++ b/server/nativeapi/delete_many_response_test.go
@@ -29,8 +29,6 @@ var _ = Describe("writeDeleteManyResponse", func() {
 		Expect(write("a", "b")).To(HaveKeyWithValue("ids", ConsistOf("a", "b")))
 	})
 
-	// ids come straight from the query string. html.EscapeString, used previously to
-	// build the single-id body, does not escape backslashes, so `{"id":"a\"}` went out.
 	It("stays valid JSON when the id contains a backslash", func() {
 		Expect(write(`a\`)).To(HaveKeyWithValue("id", `a\`))
 	})
@@ -43,8 +41,9 @@ var _ = Describe("writeDeleteManyResponse", func() {
 		Expect(write("a&b")).To(HaveKeyWithValue("id", "a&b"))
 	})
 
-	It("responds 200 on success", func() {
+	It("responds 200 with a JSON content type", func() {
 		write("abc123")
 		Expect(w.Code).To(Equal(http.StatusOK))
+		Expect(w.Header().Get("Content-Type")).To(Equal("application/json"))
 	})
 })
diff --git a/server/nativeapi/native_api.go b/server/nativeapi/native_api.go
index 3476ec5a0..a7c53df09 100644
--- a/server/nativeapi/native_api.go
+++ b/server/nativeapi/native_api.go
@@ -2,7 +2,6 @@ package nativeapi
 
 import (
 	"context"
-	"encoding/json"
 	"net/http"
 	"strconv"
 	"time"
@@ -205,9 +204,6 @@ func (api *Router) addMissingFilesRoute(r chi.Router) {
 }
 
 func writeDeleteManyResponse(w http.ResponseWriter, r *http.Request, ids []string) {
-	// Marshal both shapes instead of building the single-id case by hand: ids come
-	// from the query string, and html.EscapeString leaves backslashes untouched, so
-	// an id containing one produced a malformed body.
 	var payload any
 	if len(ids) == 1 {
 		payload = struct {
@@ -218,13 +214,7 @@ func writeDeleteManyResponse(w http.ResponseWriter, r *http.Request, ids []strin
 			Ids []string `json:"ids"`
 		}{Ids: ids}
 	}
-	resp, err := json.Marshal(payload)
-	if err != nil {
-		log.Error(r.Context(), "Error marshaling response", "ids", ids, err)
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	if _, err := w.Write(resp); err != nil {
+	if err := rest.RespondWithJSON(w, http.StatusOK, payload); err != nil {
 		log.Error(r.Context(), "Error writing response", "ids", ids, err)
 	}
 }
diff --git a/server/public/handle_shares.go b/server/public/handle_shares.go
index b69549e7c..367bff501 100644
--- a/server/public/handle_shares.go
+++ b/server/public/handle_shares.go
@@ -58,7 +58,6 @@ func (pub *Router) handleM3U(w http.ResponseWriter, r *http.Request) {
 	}
 
 	s = pub.mapShareToM3U(r, *s)
-	// Content-Type must be set before WriteHeader, otherwise it is dropped
 	w.Header().Set("Content-Type", "audio/x-mpegurl")
 	w.WriteHeader(http.StatusOK)
 	_, _ = w.Write([]byte(s.ToM3U8())) //nolint:gosec
diff --git a/server/public/handle_shares_test.go b/server/public/handle_shares_test.go
index b299f4cfd..1bf631fd4 100644
--- a/server/public/handle_shares_test.go
+++ b/server/public/handle_shares_test.go
@@ -30,7 +30,6 @@ var _ = Describe("handleM3U", func() {
 		return w
 	}
 
-	// Content-Type used to be set after WriteHeader, which silently drops it.
 	It("sets the M3U content type", func() {
 		share := &model.Share{ID: "abc123", Tracks: model.MediaFiles{{ID: "t1", Title: "Track 1"}}}
 		shareRepo.ID = share.ID
@@ -39,9 +38,7 @@ var _ = Describe("handleM3U", func() {
 		w := makeRequest("abc123")
 
 		Expect(w.Code).To(Equal(http.StatusOK))
-		// Result() reports the headers as they were when WriteHeader ran, which is
-		// what the client actually receives. w.Header() would still show a
-		// Content-Type set too late to be sent.
+		// Result() has the headers sent at WriteHeader time, unlike w.Header()
 		Expect(w.Result().Header.Get("Content-Type")).To(Equal("audio/x-mpegurl"))
 		Expect(w.Body.String()).To(HavePrefix("#EXTM3U"))
 	})