diff --git a/packages/core/src/api/index.ts b/packages/core/src/api/index.ts
index 20815e6bc..5049d3801 100644
--- a/packages/core/src/api/index.ts
+++ b/packages/core/src/api/index.ts
@@ -95,6 +95,7 @@ class Database {
   isInitialized = false;
   eventManager = new EventManager();
   sseMutex = new Mutex();
+  _fs?: FileStorage;
 
   storage: StorageAccessor = () => {
     if (!this.options?.storage)
@@ -109,7 +110,10 @@ class Database {
       throw new Error(
         "Database not initialized. Did you forget to call db.setup()?"
       );
-    return new FileStorage(this.options.fs, this.tokenManager);
+    return (
+      this._fs ||
+      (this._fs = new FileStorage(this.options.fs, this.tokenManager))
+    );
   };
 
   crypto: CryptoAccessor = () => {
diff --git a/packages/core/src/database/fs.ts b/packages/core/src/database/fs.ts
index 9d65d1a31..51fa1aba5 100644
--- a/packages/core/src/database/fs.ts
+++ b/packages/core/src/database/fs.ts
@@ -30,16 +30,22 @@ import { logger } from "../logger";
 export type FileStorageAccessor = () => FileStorage;
 export type DownloadableFile = {
   filename: string;
-  // metadata: AttachmentMetadata;
   chunkSize: number;
 };
 export type QueueItem = DownloadableFile & {
   cancel?: (reason?: string) => Promise<void>;
+  operation?: Promise<boolean>;
 };
 
 export class FileStorage {
-  downloads = new Map<string, QueueItem[]>();
-  uploads = new Map<string, QueueItem[]>();
+  id = Date.now();
+  downloads = new Map<string, QueueItem>();
+  uploads = new Map<string, QueueItem>();
+  groups = {
+    downloads: new Map<string, Set<string>>(),
+    uploads: new Map<string, Set<string>>()
+  };
+
   constructor(
     private readonly fs: IFileStorage,
     private readonly tokenManager: TokenManager
@@ -50,12 +56,26 @@ export class FileStorage {
     groupId: string,
     eventData?: Record<string, unknown>
   ) {
+    let current = 0;
     const token = await this.tokenManager.getAccessToken();
     const total = files.length;
-    let current = 0;
-    this.downloads.set(groupId, files);
+    const group = this.groups.downloads.get(groupId) || new Set();
+    files.forEach((f) => group.add(f.filename));
+    this.groups.downloads.set(groupId, group);
 
     for (const file of files as QueueItem[]) {
+      if (!group.has(file.filename)) continue;
+
+      const download = this.downloads.get(file.filename);
+      if (download && download.operation) {
+        logger.debug("[queueDownloads] duplicate download", {
+          filename: file.filename,
+          groupId
+        });
+        await download.operation;
+        continue;
+      }
+
       const { filename, chunkSize } = file;
       if (await this.exists(filename)) {
         current++;
@@ -68,14 +88,6 @@ export class FileStorage {
         continue;
       }
 
-      const url = `${hosts.API_HOST}/s3?name=${filename}`;
-      const { execute, cancel } = this.fs.downloadFile(filename, {
-        url,
-        chunkSize,
-        headers: { Authorization: `Bearer ${token}` }
-      });
-      file.cancel = cancel;
-
       EV.publish(EVENTS.fileDownload, {
         total,
         current,
@@ -83,7 +95,22 @@ export class FileStorage {
         filename
       });
 
-      const result = await execute().catch(() => false);
+      const url = `${hosts.API_HOST}/s3?name=${filename}`;
+      const { execute, cancel } = this.fs.downloadFile(filename, {
+        url,
+        chunkSize,
+        headers: { Authorization: `Bearer ${token}` }
+      });
+      file.cancel = cancel;
+      file.operation = execute()
+        .catch(() => false)
+        .finally(() => {
+          this.downloads.delete(filename);
+          group.delete(filename);
+        });
+
+      this.downloads.set(filename, file);
+      const result = await file.operation;
       if (eventData)
         EV.publish(EVENTS.fileDownloaded, {
           success: result,
@@ -94,17 +121,31 @@ export class FileStorage {
           eventData
         });
     }
-    this.downloads.delete(groupId);
   }
 
   async queueUploads(files: DownloadableFile[], groupId: string) {
+    let current = 0;
     const token = await this.tokenManager.getAccessToken();
     const total = files.length;
-    let current = 0;
-    this.uploads.set(groupId, files);
+    const group = this.groups.uploads.get(groupId) || new Set();
+    files.forEach((f) => group.add(f.filename));
+    this.groups.uploads.set(groupId, group);
 
     for (const file of files as QueueItem[]) {
+      if (!group.has(file.filename)) continue;
+
+      const upload = this.uploads.get(file.filename);
+      if (upload && upload.operation) {
+        logger.debug("[queueUploads] duplicate upload", {
+          filename: file.filename,
+          groupId
+        });
+        await file.operation;
+        continue;
+      }
+
       const { filename, chunkSize } = file;
+      let error = null;
       const url = `${hosts.API_HOST}/s3?name=${filename}`;
       const { execute, cancel } = this.fs.uploadFile(filename, {
         chunkSize,
@@ -112,6 +153,16 @@ export class FileStorage {
         headers: { Authorization: `Bearer ${token}` }
       });
       file.cancel = cancel;
+      file.operation = execute()
+        .catch((e) => {
+          logger.error(e, "failed to upload attachment", { hash: filename });
+          error = e;
+          return false;
+        })
+        .finally(() => {
+          this.uploads.delete(filename);
+          group.delete(filename);
+        });
 
       EV.publish(EVENTS.fileUpload, {
         total,
@@ -120,13 +171,8 @@ export class FileStorage {
         filename
       });
 
-      let error = null;
-      const result = await execute().catch((e) => {
-        logger.error(e, "failed to upload attachment", { hash: filename });
-        error = e;
-        return false;
-      });
-
+      this.uploads.set(filename, file);
+      const result = await file.operation;
       EV.publish(EVENTS.fileUploaded, {
         error,
         success: result,
@@ -136,44 +182,67 @@ export class FileStorage {
         filename
       });
     }
-    this.uploads.delete(groupId);
   }
 
   async downloadFile(groupId: string, filename: string, chunkSize: number) {
+    if (await this.exists(filename)) return true;
+
+    const download = this.downloads.get(filename);
+    if (download && download.operation) {
+      logger.debug("[downloadFile] duplicate download", { filename, groupId });
+      return await download.operation;
+    }
+
     logger.debug("[downloadFile] downloading", { filename, groupId });
 
     const url = `${hosts.API_HOST}/s3?name=${filename}`;
+    const file: QueueItem = { filename, chunkSize };
     const token = await this.tokenManager.getAccessToken();
+    const group = this.groups.downloads.get(groupId) || new Set();
     const { execute, cancel } = this.fs.downloadFile(filename, {
       url,
       chunkSize,
       headers: { Authorization: `Bearer ${token}` }
     });
-    this.downloads.set(groupId, [{ cancel, filename, chunkSize }]);
-    const result = await execute();
-    this.downloads.delete(groupId);
-    return result;
+    file.cancel = cancel;
+    file.operation = execute().finally(() => {
+      this.downloads.delete(filename);
+      group.delete(filename);
+    });
+
+    this.downloads.set(filename, file);
+    this.groups.downloads.set(groupId, group.add(filename));
+    return await file.operation;
   }
 
   async cancel(groupId: string) {
     const queues = [
-      { type: "download", files: this.downloads.get(groupId) },
-      { type: "upload", files: this.uploads.get(groupId) }
-    ].filter((a) => !!a.files);
+      {
+        type: "download",
+        ids: this.groups.downloads.get(groupId),
+        files: this.downloads
+      },
+      {
+        type: "upload",
+        ids: this.groups.uploads.get(groupId),
+        files: this.uploads
+      }
+    ].filter((a) => !!a.ids);
 
     for (const queue of queues) {
-      if (!queue.files) continue;
-      for (let i = 0; i < queue.files.length; ++i) {
-        const file = queue.files[i];
-        if (file.cancel) await file.cancel("Operation canceled.");
-        queue.files.splice(i, 1);
+      if (!queue.ids) continue;
+
+      for (const filename of queue.ids) {
+        const file = queue.files.get(filename);
+        if (file?.cancel) await file.cancel("Operation canceled.");
+        queue.ids.delete(filename);
       }
 
       if (queue.type === "download") {
-        this.downloads.delete(groupId);
+        this.groups.downloads.delete(groupId);
         EV.publish(EVENTS.downloadCanceled, { groupId, canceled: true });
       } else if (queue.type === "upload") {
-        this.uploads.delete(groupId);
+        this.groups.uploads.delete(groupId);
         EV.publish(EVENTS.uploadCanceled, { groupId, canceled: true });
       }
     }