diff --git a/packages/file-selector/src/lib/ErrorAlert.test.tsx b/packages/file-selector/src/lib/ErrorAlert.test.tsx
index 74ad1ae1b..85313e8e4 100644
--- a/packages/file-selector/src/lib/ErrorAlert.test.tsx
+++ b/packages/file-selector/src/lib/ErrorAlert.test.tsx
@@ -12,6 +12,7 @@ describe('ErrorAlert', () => {
 
 describe('formatFileTooLarge', () => {
   test('should format file too large error message', () => {
+    // 10 MiB = 10 * 1024 * 1024 = 10485760 bytes
     const formattedError = formatFileTooLarge('File is larger than 10485760 bytes');
 
     expect(formattedError).toEqual('File is larger than 10 MB');
diff --git a/packages/file-selector/src/lib/ErrorAlert.tsx b/packages/file-selector/src/lib/ErrorAlert.tsx
index f551baef1..ece05c04b 100644
--- a/packages/file-selector/src/lib/ErrorAlert.tsx
+++ b/packages/file-selector/src/lib/ErrorAlert.tsx
@@ -1,7 +1,7 @@
 import { Alert, AlertTitle } from '@availity/mui-alert';
 import { List, ListItem } from '@availity/mui-list';
-import type { FileRejection } from 'react-dropzone';
-import { formatBytes } from './util';
+import type { FileError, FileRejection } from 'react-dropzone';
+import { dedupeErrors, formatBytes } from './util';
 
 const codes: Record<string, string> = {
   'file-too-large': 'File exceeds maximum size',
@@ -12,6 +12,8 @@ const codes: Record<string, string> = {
   'duplicate-name': 'Duplicate file selected',
 };
 
+export type GetErrorMessageFn = (error: FileError) => string | null | undefined;
+
 export type ErrorAlertProps = {
   /**
    * Array of file rejection errors
@@ -25,6 +27,10 @@ export type ErrorAlertProps = {
    * Unique identifier for the error alert
    */
   id: number;
+  /**
+   * Custom function to format error messages. Return null/undefined to use default message.
+   */
+  getErrorMessage?: GetErrorMessageFn;
 
   onClose: () => void;
 };
@@ -41,15 +47,30 @@ export const formatFileTooLarge = (message: string): string => {
   return message.replace(` bytes`, '').replace(FILE_SIZE_REGEX, formattedSize);
 };
 
-export const ErrorAlert = ({ errors, fileName, id, onClose }: ErrorAlertProps) => {
+export const ErrorAlert = ({ errors, fileName, id, getErrorMessage, onClose }: ErrorAlertProps) => {
   if (errors.length === 0) return null;
 
+  // Dedupe errors by code (e.g., react-dropzone may produce multiple file-invalid-type errors)
+  const uniqueErrors = dedupeErrors(errors);
+
+  const formatMessage = (error: FileRejection['errors'][0]) => {
+    // Try custom error message first
+    const customMessage = getErrorMessage?.(error);
+    if (customMessage) return customMessage;
+    
+    // Fall back to default formatting
+    if (error.code === 'file-too-large') {
+      return formatFileTooLarge(error.message);
+    }
+    return error.message;
+  };
+
   return (
     <Alert severity="error" onClose={onClose}>
-      {errors.length > 1 ? (
+      {uniqueErrors.length > 1 ? (
         <>
           <AlertTitle>
-            There were {errors.length} error(s) found when uploading {fileName}
+            There were {uniqueErrors.length} error(s) found when uploading {fileName}
           </AlertTitle>
           <List
             sx={{
@@ -63,23 +84,20 @@ export const ErrorAlert = ({ errors, fileName, id, onClose }: ErrorAlertProps) =
             disablePadding
           >
             <>
-              {errors.map((error) => {
-                const message = error.code === 'file-too-large' ? formatFileTooLarge(error.message) : error.message;
-                return (
-                  <ListItem disableGutters disablePadding divider={false} key={`${id}-${error.code}`}>
-                    {message}
-                  </ListItem>
-                );
-              })}
+              {uniqueErrors.map((error) => (
+                <ListItem disableGutters disablePadding divider={false} key={`${id}-${error.code}`}>
+                  {formatMessage(error)}
+                </ListItem>
+              ))}
             </>
           </List>
         </>
       ) : (
         <>
           <AlertTitle>
-            {codes[errors[0].code] || 'Error'}: {fileName}
+            {codes[uniqueErrors[0].code] || 'Error'}: {fileName}
           </AlertTitle>
-          {errors[0].code === 'file-too-large' ? formatFileTooLarge(errors[0].message) : errors[0].message}
+          {formatMessage(uniqueErrors[0])}
         </>
       )}
     </Alert>
diff --git a/packages/file-selector/src/lib/FileSelector.tsx b/packages/file-selector/src/lib/FileSelector.tsx
index 3d5ceb7dc..dbaf459dd 100644
--- a/packages/file-selector/src/lib/FileSelector.tsx
+++ b/packages/file-selector/src/lib/FileSelector.tsx
@@ -9,7 +9,7 @@ import { Typography } from '@availity/mui-typography';
 import { Alert, AlertTitle } from '@availity/mui-alert';
 
 import { Dropzone } from './Dropzone';
-import { ErrorAlert } from './ErrorAlert';
+import { ErrorAlert, GetErrorMessageFn } from './ErrorAlert';
 import { FileList } from './FileList';
 import { FileTypesMessage } from './FileTypesMessage';
 import { HeaderMessage } from './HeaderMessage';
@@ -147,6 +147,12 @@ export type FileSelectorProps = {
    * @default false
    */
   disableRemove?: boolean;
+  /**
+   * Custom function to format error messages. Return undefined to use default message.
+   * @param error - The file error object with code and message
+   * @returns Custom error message string, or undefined to use default
+   */
+  getErrorMessage?: GetErrorMessageFn;
 };
 
 export const FileSelector = ({
@@ -177,6 +183,7 @@ export const FileSelector = ({
   uploadOptions,
   validator,
   disableRemove,
+  getErrorMessage,
 }: FileSelectorProps) => {
   const [totalSize, setTotalSize] = useState(0);
   const [fileRejections, setFileRejections] = useState<(FileRejection & { id: number })[]>([]);
@@ -323,6 +330,7 @@ export const FileSelector = ({
             errors={rejection.errors}
             fileName={rejection.file.name}
             id={rejection.id}
+            getErrorMessage={getErrorMessage}
             onClose={() => handleRemoveRejection(rejection.id)}
           />
         ))}
diff --git a/packages/file-selector/src/lib/FileSelector2.tsx b/packages/file-selector/src/lib/FileSelector2.tsx
index a203a4d22..ab164cd25 100644
--- a/packages/file-selector/src/lib/FileSelector2.tsx
+++ b/packages/file-selector/src/lib/FileSelector2.tsx
@@ -7,7 +7,7 @@ import { Typography } from '@availity/mui-typography';
 import { Alert, AlertTitle } from '@availity/mui-alert';
 
 import { Dropzone2 } from './Dropzone2';
-import { ErrorAlert } from './ErrorAlert';
+import { ErrorAlert, GetErrorMessageFn } from './ErrorAlert';
 import { FileList2 } from './FileList2';
 import { FileTypesMessage } from './FileTypesMessage';
 import { HeaderMessage } from './HeaderMessage';
@@ -18,6 +18,12 @@ import type { FileSelectorProps } from './FileSelector';
 
 export type FileSelector2Props = Omit<FileSelectorProps, 'onUploadRemove' | 'queryOptions'> & {
   onUploadRemove?: (uploads: Upload[], removedUploadId: string) => void;
+  /**
+   * Custom function to format error messages. Return undefined to use default message.
+   * @param error - The file error object with code and message
+   * @returns Custom error message string, or undefined to use default
+   */
+  getErrorMessage?: GetErrorMessageFn;
 };
 
 /**
@@ -56,6 +62,7 @@ export const FileSelector2 = ({
   uploadOptions,
   validator,
   disableRemove,
+  getErrorMessage,
 }: FileSelector2Props) => {
   const [totalSize, setTotalSize] = useState(0);
   const [fileRejections, setFileRejections] = useState<(FileRejection & { id: number })[]>([]);
@@ -200,6 +207,7 @@ export const FileSelector2 = ({
             errors={rejection.errors}
             fileName={rejection.file.name}
             id={rejection.id}
+            getErrorMessage={getErrorMessage}
             onClose={() => handleRemoveRejection(rejection.id)}
           />
         ))}
diff --git a/packages/file-selector/src/lib/UploadProgressBar.tsx b/packages/file-selector/src/lib/UploadProgressBar.tsx
index 3af621303..e18f02b8e 100644
--- a/packages/file-selector/src/lib/UploadProgressBar.tsx
+++ b/packages/file-selector/src/lib/UploadProgressBar.tsx
@@ -42,6 +42,10 @@ const ERROR_MAPPINGS: ErrorMapping[] = [
     pattern: /but has an extension for/i,
     friendlyMessage: 'File format does not match file extension.',
   },
+  {
+    pattern: /tus: failed to upload/i,
+    friendlyMessage: 'Oops! There was an issue trying to upload your attachment.',
+  },
 ];
 
 const friendlyErrorMessage = (errorMessage: string): string => {
diff --git a/packages/file-selector/src/lib/util.ts b/packages/file-selector/src/lib/util.ts
index b457fabb2..6949f1607 100644
--- a/packages/file-selector/src/lib/util.ts
+++ b/packages/file-selector/src/lib/util.ts
@@ -21,7 +21,7 @@ export function formatBytes(bytes: number, decimals = 2) {
 
   const i = Math.floor(Math.log(bytes) / Math.log(k));
 
-  return `${Number.parseFloat((bytes / k**i).toFixed(dm))} ${sizes[i]}`;
+  return `${Number.parseFloat((bytes / k ** i).toFixed(dm))} ${sizes[i]}`;
 }
 export const FILE_EXT_ICONS = {
   png: FileImageIcon,