diff --git a/src/core/Core.js b/src/core/Core.js
index 8d5558a00..9ed43bf30 100644
--- a/src/core/Core.js
+++ b/src/core/Core.js
@@ -296,8 +296,8 @@ class Uppy {
       .then(() => this.opts.onBeforeFileAdded(file, this.getState().files))
 
     return beforeFileAdded.catch((err) => {
-      this.info(err, 'error', 5000)
-      return Promise.reject(`onBeforeFileAdded: ${err}`)
+      this.info(err.message, 'error', 5000)
+      return Promise.reject(new Error(`onBeforeFileAdded: ${err}`))
     }).then(() => {
       return Utils.getFileType(file).then((fileType) => {
         const updatedFiles = Object.assign({}, this.state.files)
@@ -335,7 +335,7 @@ class Uppy {
         }
 
         const isFileAllowed = this.checkRestrictions(newFile)
-        if (!isFileAllowed) return Promise.reject('File not allowed')
+        if (!isFileAllowed) return Promise.reject(new Error('File not allowed'))
 
         updatedFiles[fileID] = newFile
         this.setState({files: updatedFiles})
@@ -935,15 +935,15 @@ class Uppy {
   upload (forceUpload) {
     const isMinNumberOfFilesReached = this.checkMinNumberOfFiles()
     if (!isMinNumberOfFilesReached) {
-      return Promise.reject('Minimum number of files has not been reached')
+      return Promise.reject(new Error('Minimum number of files has not been reached'))
     }
 
     const beforeUpload = Promise.resolve()
       .then(() => this.opts.onBeforeUpload(this.state.files))
 
     return beforeUpload.catch((err) => {
-      this.info(err, 'error', 5000)
-      return Promise.reject(`onBeforeUpload: ${err}`)
+      this.info(err.message, 'error', 5000)
+      return Promise.reject(new Error(`onBeforeUpload: ${err}`))
     }).then(() => {
       const waitingFileIDs = []
       Object.keys(this.state.files).forEach((fileID) => {
diff --git a/src/core/Core.test.js b/src/core/Core.test.js
index 7398354f2..468aa38d6 100644
--- a/src/core/Core.test.js
+++ b/src/core/Core.test.js
@@ -567,7 +567,7 @@ describe('src/Core', () => {
           throw new Error('File was allowed through')
         })
         .catch(e => {
-          expect(e).toEqual('File not allowed')
+          expect(e.message).toEqual('File not allowed')
         })
     })
   })
@@ -720,7 +720,7 @@ describe('src/Core', () => {
         name: 'foo2.jpg',
         type: 'image/jpg',
         data: utils.dataURItoFile(sampleImageDataURI, {})
-      })).rejects.toMatch('File not allowed').then(() => {
+      })).rejects.toMatchObject({ message: 'File not allowed' }).then(() => {
         expect(core.state.info.message).toEqual('You can only upload 1 file')
       })
     })
@@ -740,7 +740,7 @@ describe('src/Core', () => {
         name: 'foo2.jpg',
         type: 'image/jpg',
         data: utils.dataURItoFile(sampleImageDataURI, {})
-      })).rejects.toMatch('File not allowed').then(() => {
+      })).rejects.toMatchObject({ message: 'File not allowed' }).then(() => {
         expect(core.state.info.message).toEqual('You can only upload: image/gif, image/png')
       })
     })
@@ -758,7 +758,7 @@ describe('src/Core', () => {
         name: 'foo.jpg',
         type: 'image/jpg',
         data: utils.dataURItoFile(sampleImageDataURI, {})
-      })).rejects.toMatch('File not allowed').then(() => {
+      })).rejects.toMatchObject({ message: 'File not allowed' }).then(() => {
         expect(core.state.info.message).toEqual('This file exceeds maximum allowed size of 1.2 KB')
       })
     })
diff --git a/src/core/Utils.js b/src/core/Utils.js
index 0d8bafc5f..6b8d0210e 100644
--- a/src/core/Utils.js
+++ b/src/core/Utils.js
@@ -367,7 +367,7 @@ function copyToClipboard (textToCopy, fallbackString) {
     const magicCopyFailed = (err) => {
       document.body.removeChild(textArea)
       window.prompt(fallbackString, textToCopy)
-      return reject('Oops, unable to copy displayed fallback prompt: ' + err)
+      return reject(new Error('Oops, unable to copy displayed fallback prompt: ' + err))
     }
 
     try {
diff --git a/src/plugins/Tus10.js b/src/plugins/Tus10.js
index b85df6b01..923de71b3 100644
--- a/src/plugins/Tus10.js
+++ b/src/plugins/Tus10.js
@@ -143,7 +143,7 @@ module.exports = class Tus10 extends Plugin {
       optsTus.onError = (err) => {
         this.core.log(err)
         this.core.emit('core:upload-error', file.id, err)
-        reject('Failed because: ' + err)
+        reject(new Error('Failed because: ' + err))
       }
 
       optsTus.onProgress = (bytesUploaded, bytesTotal) => {
diff --git a/src/plugins/Webcam/index.js b/src/plugins/Webcam/index.js
index 35bc3e8e9..30eca92a5 100644
--- a/src/plugins/Webcam/index.js
+++ b/src/plugins/Webcam/index.js
@@ -199,7 +199,7 @@ module.exports = class Webcam extends Plugin {
         if (!this.webcamActive) {
           clearInterval(countDown)
           this.captureInProgress = false
-          return reject('Webcam is not active')
+          return reject(new Error('Webcam is not active'))
         }
 
         if (count > 0) {
@@ -234,12 +234,12 @@ module.exports = class Webcam extends Plugin {
 
     this.opts.onBeforeSnapshot().catch((err) => {
       this.core.info(err, 'error', 5000)
-      return Promise.reject(`onBeforeSnapshot: ${err}`)
+      return Promise.reject(new Error(`onBeforeSnapshot: ${err}`))
     }).then(() => {
       const video = this.target.querySelector('.UppyWebcam-video')
       if (!video) {
         this.captureInProgress = false
-        return Promise.reject('No video element found, likely due to the Webcam tab being closed.')
+        return Promise.reject(new Error('No video element found, likely due to the Webcam tab being closed.'))
       }
 
       const image = this.webcam.getImage(video, opts)