diff --git a/bindings/matrix-sdk-ffi/src/sliding_sync.rs b/bindings/matrix-sdk-ffi/src/sliding_sync.rs
index 6f149a7fd..0130fff32 100644
--- a/bindings/matrix-sdk-ffi/src/sliding_sync.rs
+++ b/bindings/matrix-sdk-ffi/src/sliding_sync.rs
@@ -110,11 +110,6 @@ pub enum SlidingSyncError {
     BadResponse {
         msg: String,
     },
-    /// Called `.build()` on a builder type, but the given required field was
-    /// missing.
-    BuildMissingField {
-        msg: String,
-    },
     /// A `SlidingSyncListRequestGenerator` has been used without having been
     /// initialized. It happens when a response is handled before a request has
     /// been sent. It usually happens when testing.
@@ -144,7 +139,6 @@ impl From<matrix_sdk::sliding_sync::Error> for SlidingSyncError {
 
         match value {
             E::BadResponse(msg) => Self::BadResponse { msg },
-            E::BuildMissingField(msg) => Self::BuildMissingField { msg: msg.to_owned() },
             E::RequestGeneratorHasNotBeenInitialized(msg) => {
                 Self::RequestGeneratorHasNotBeenInitialized { msg }
             }
diff --git a/crates/matrix-sdk/src/sliding_sync/builder.rs b/crates/matrix-sdk/src/sliding_sync/builder.rs
index b263d5e48..f10aabf53 100644
--- a/crates/matrix-sdk/src/sliding_sync/builder.rs
+++ b/crates/matrix-sdk/src/sliding_sync/builder.rs
@@ -16,7 +16,7 @@ use ruma::{
 use url::Url;
 
 use super::{
-    cache::restore_sliding_sync_state, Error, SlidingSync, SlidingSyncInner, SlidingSyncList,
+    cache::restore_sliding_sync_state, SlidingSync, SlidingSyncInner, SlidingSyncList,
     SlidingSyncPositionMarkers, SlidingSyncRoom,
 };
 use crate::{Client, Result};
@@ -29,7 +29,7 @@ use crate::{Client, Result};
 pub struct SlidingSyncBuilder {
     storage_key: Option<String>,
     homeserver: Option<Url>,
-    client: Option<Client>,
+    client: Client,
     lists: BTreeMap<String, SlidingSyncList>,
     bump_event_types: Vec<TimelineEventType>,
     extensions: Option<ExtensionsConfig>,
@@ -37,11 +37,11 @@ pub struct SlidingSyncBuilder {
 }
 
 impl SlidingSyncBuilder {
-    pub(super) fn new() -> Self {
+    pub(super) fn new(client: Client) -> Self {
         Self {
             storage_key: None,
             homeserver: None,
-            client: None,
+            client,
             lists: BTreeMap::new(),
             bump_event_types: Vec::new(),
             extensions: None,
@@ -61,12 +61,6 @@ impl SlidingSyncBuilder {
         self
     }
 
-    /// Set the client this sliding sync will be using.
-    pub fn client(mut self, value: Client) -> Self {
-        self.client = Some(value);
-        self
-    }
-
     /// Add the given list to the lists.
     ///
     /// Replace any list with the name.
@@ -207,7 +201,7 @@ impl SlidingSyncBuilder {
     /// If `self.storage_key` is `Some(_)`, load the cached data from cold
     /// storage.
     pub async fn build(mut self) -> Result<SlidingSync> {
-        let client = self.client.ok_or(Error::BuildMissingField("client"))?;
+        let client = self.client;
 
         let mut delta_token = None;
         let mut rooms_found: BTreeMap<OwnedRoomId, SlidingSyncRoom> = BTreeMap::new();
diff --git a/crates/matrix-sdk/src/sliding_sync/client.rs b/crates/matrix-sdk/src/sliding_sync/client.rs
index 68bb3ce63..be496f0f0 100644
--- a/crates/matrix-sdk/src/sliding_sync/client.rs
+++ b/crates/matrix-sdk/src/sliding_sync/client.rs
@@ -8,7 +8,7 @@ use crate::{Client, Result};
 impl Client {
     /// Create a [`SlidingSyncBuilder`] tied to this client.
     pub async fn sliding_sync(&self) -> SlidingSyncBuilder {
-        SlidingSync::builder().client(self.clone())
+        SlidingSync::builder(self.clone())
     }
 
     #[instrument(skip(self, response))]
diff --git a/crates/matrix-sdk/src/sliding_sync/error.rs b/crates/matrix-sdk/src/sliding_sync/error.rs
index bacea352f..41baaef19 100644
--- a/crates/matrix-sdk/src/sliding_sync/error.rs
+++ b/crates/matrix-sdk/src/sliding_sync/error.rs
@@ -12,10 +12,6 @@ pub enum Error {
     /// `sync`-restart might be required.
     #[error("The sliding sync response could not be handled: {0}")]
     BadResponse(String),
-    /// Called `.build()` on a builder type, but the given required field was
-    /// missing.
-    #[error("Required field missing: `{0}`")]
-    BuildMissingField(&'static str),
     /// A `SlidingSyncListRequestGenerator` has been used without having been
     /// initialized. It happens when a response is handled before a request has
     /// been sent. It usually happens when testing.
diff --git a/crates/matrix-sdk/src/sliding_sync/mod.rs b/crates/matrix-sdk/src/sliding_sync/mod.rs
index 583f43993..115e134e4 100644
--- a/crates/matrix-sdk/src/sliding_sync/mod.rs
+++ b/crates/matrix-sdk/src/sliding_sync/mod.rs
@@ -125,8 +125,8 @@ impl SlidingSync {
     }
 
     /// Create a new [`SlidingSyncBuilder`].
-    pub fn builder() -> SlidingSyncBuilder {
-        SlidingSyncBuilder::new()
+    pub fn builder(client: Client) -> SlidingSyncBuilder {
+        SlidingSyncBuilder::new(client)
     }
 
     /// Subscribe to a given room.