diff --git a/src/app/api/auth/check-email/route.ts b/src/app/api/auth/check-email/route.ts
index 9c62a02..7b029e1 100644
--- a/src/app/api/auth/check-email/route.ts
+++ b/src/app/api/auth/check-email/route.ts
@@ -24,8 +24,8 @@ export async function POST(req: NextRequest) {
       return NextResponse.json({ exists: false }, { status: 400 })
     }
 
-    const user = await prisma.user.findUnique({
-      where: { email: email.toLowerCase().trim() },
+    const user = await prisma.user.findFirst({
+      where: { email: { equals: email.toLowerCase().trim(), mode: 'insensitive' } },
       select: { status: true },
     })
 
diff --git a/src/lib/auth.ts b/src/lib/auth.ts
index bd88afc..c4ad594 100644
--- a/src/lib/auth.ts
+++ b/src/lib/auth.ts
@@ -62,8 +62,8 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
         // Send magic links to any existing, non-suspended user.
         // This is the primary first-login path for applicants seeded from CSV
         // (status NONE) who have no password yet.
-        const existingUser = await prisma.user.findUnique({
-          where: { email: email.toLowerCase().trim() },
+        const existingUser = await prisma.user.findFirst({
+          where: { email: { equals: email.toLowerCase().trim(), mode: 'insensitive' } },
           select: { id: true, status: true },
         })
         if (!existingUser || existingUser.status === 'SUSPENDED') {
@@ -164,9 +164,9 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
           throw new Error('Account temporarily locked due to too many failed attempts. Try again later.')
         }
 
-        // Find user by email
-        const user = await prisma.user.findUnique({
-          where: { email },
+        // Find user by email (case-insensitive — DB may store mixed-case emails)
+        const user = await prisma.user.findFirst({
+          where: { email: { equals: email, mode: 'insensitive' } },
           select: {
             id: true,
             email: true,
@@ -371,8 +371,8 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
     async signIn({ user, account }) {
       // For email provider (magic link), check user status and get password info
       if (account?.provider === 'email') {
-        const dbUser = await prisma.user.findUnique({
-          where: { email: user.email! },
+        const dbUser = await prisma.user.findFirst({
+          where: { email: { equals: user.email!, mode: 'insensitive' } },
           select: {
             id: true,
             status: true,
@@ -404,22 +404,24 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
 
       // Update last login time on actual sign-in, and activate INVITED users on login
       if (user.email) {
-        const loginUser = await prisma.user.findUnique({
-          where: { email: user.email },
-          select: { status: true },
-        })
-        await prisma.user.update({
-          where: { email: user.email },
-          data: {
-            lastLoginAt: new Date(),
-            // If user is still INVITED but successfully logged in, activate them
-            ...(loginUser && loginUser.status === 'INVITED'
-              ? { status: 'ACTIVE' }
-              : {}),
-          },
-        }).catch(() => {
-          // Ignore errors from updating last login
+        const loginUser = await prisma.user.findFirst({
+          where: { email: { equals: user.email, mode: 'insensitive' } },
+          select: { id: true, status: true },
         })
+        if (loginUser) {
+          await prisma.user.update({
+            where: { id: loginUser.id },
+            data: {
+              lastLoginAt: new Date(),
+              // If user is still INVITED but successfully logged in, activate them
+              ...(loginUser.status === 'INVITED'
+                ? { status: 'ACTIVE' }
+                : {}),
+            },
+          }).catch(() => {
+            // Ignore errors from updating last login
+          })
+        }
 
         // Log successful login
         await prisma.auditLog.create({
diff --git a/src/server/routers/user.ts b/src/server/routers/user.ts
index c76f100..0aedf67 100644
--- a/src/server/routers/user.ts
+++ b/src/server/routers/user.ts
@@ -1595,9 +1595,9 @@ export const userRouter = router({
     .mutation(async ({ ctx, input }) => {
       const email = input.email.toLowerCase().trim()
 
-      // Find user by email
-      const user = await ctx.prisma.user.findUnique({
-        where: { email },
+      // Find user by email (case-insensitive — DB may store mixed-case emails)
+      const user = await ctx.prisma.user.findFirst({
+        where: { email: { equals: email, mode: 'insensitive' } },
         select: { id: true, email: true, name: true, status: true },
       })