diff --git a/packages/@uppy/core/src/index.js b/packages/@uppy/core/src/index.js
index 6361173089..ea18732b6d 100644
--- a/packages/@uppy/core/src/index.js
+++ b/packages/@uppy/core/src/index.js
@@ -402,21 +402,6 @@ class Uppy {
       onError(new Error('Cannot add new files: already uploading.'))
     }
 
-    const onBeforeFileAddedResult = this.opts.onBeforeFileAdded(file, files)
-
-    if (onBeforeFileAddedResult === false) {
-      this.log('Not adding file because onBeforeFileAdded returned false')
-      return
-    }
-
-    if (typeof onBeforeFileAddedResult === 'object' && onBeforeFileAddedResult) {
-      // warning after the change in 0.24
-      if (onBeforeFileAddedResult.then) {
-        throw new TypeError('onBeforeFileAdded() returned a Promise, but this is no longer supported. It must be synchronous.')
-      }
-      file = onBeforeFileAddedResult
-    }
-
     const fileType = getFileType(file)
     let fileName
     if (file.name) {
@@ -437,7 +422,7 @@ class Uppy {
 
     // `null` means the size is unknown.
     const size = isFinite(file.data.size) ? file.data.size : null
-    const newFile = {
+    let newFile = {
       source: file.source || '',
       id: fileID,
       name: fileName,
@@ -465,6 +450,17 @@ class Uppy {
       onError(err)
     }
 
+    const onBeforeFileAddedResult = this.opts.onBeforeFileAdded(newFile, files)
+
+    if (onBeforeFileAddedResult === false) {
+      this.log('Not adding file because onBeforeFileAdded returned false')
+      return
+    }
+
+    if (typeof onBeforeFileAddedResult === 'object' && onBeforeFileAddedResult) {
+      newFile = onBeforeFileAddedResult
+    }
+
     this.setState({
       files: Object.assign({}, files, {
         [fileID]: newFile
@@ -1244,6 +1240,21 @@ class Uppy {
     }
 
     let files = this.getState().files
+
+    const handleError = (err) => {
+      const message = typeof err === 'object' ? err.message : err
+      const details = typeof err === 'object' ? err.details : null
+      this.log(`${message} ${details}`)
+      this.info({ message: message, details: details }, 'error', 4000)
+      return Promise.reject(typeof err === 'object' ? err : new Error(err))
+    }
+
+    try {
+      this._checkMinNumberOfFiles(files)
+    } catch (err) {
+      return handleError(err)
+    }
+
     const onBeforeUploadResult = this.opts.onBeforeUpload(files)
 
     if (onBeforeUploadResult === false) {
@@ -1251,16 +1262,10 @@ class Uppy {
     }
 
     if (onBeforeUploadResult && typeof onBeforeUploadResult === 'object') {
-      // warning after the change in 0.24
-      if (onBeforeUploadResult.then) {
-        throw new TypeError('onBeforeUpload() returned a Promise, but this is no longer supported. It must be synchronous.')
-      }
-
       files = onBeforeUploadResult
     }
 
     return Promise.resolve()
-      .then(() => this._checkMinNumberOfFiles(files))
       .then(() => {
         const { currentUploads } = this.getState()
         // get a list of files that are currently assigned to uploads
@@ -1278,13 +1283,7 @@ class Uppy {
         const uploadID = this._createUpload(waitingFileIDs)
         return this._runUpload(uploadID)
       })
-      .catch((err) => {
-        const message = typeof err === 'object' ? err.message : err
-        const details = typeof err === 'object' ? err.details : null
-        this.log(`${message} ${details}`)
-        this.info({ message: message, details: details }, 'error', 4000)
-        return Promise.reject(typeof err === 'object' ? err : new Error(err))
-      })
+      .catch(handleError)
   }
 }