SharePrep - Prepare File Names for Import into SharePoint


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Link to the SharePrep Purchase page

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Utility for Renaming Files and Folders for SharePoint Migration

from the author of DelinvFile and PurgeIE


Great for OneDrive and OneDrive for Business Migration


Microsoft's SharePoint Migration Tool simplifies the transfer of your files to SharePoint Online or OneDrive for Business

SharePrep can be used to prepare your local files and folders for that transfer.  SharePrep can identify and correct most, if not all, of the problems related to name length and path length restrictions.

SharePrep provides functions for shortening file names, folder names and data paths.

It is more cost-effective to identify and correct problems with file names, folder names and data path lengths before attempting the actual migrations.

At a minimum, you can use SharePrep's free trial days to analyze your data for the known restrictions.


SharePrep 5.01 supports Win-10 back thru Win-7 [32 & 64 bit]


Version 5.01 implements new functionality for working only with the files and their paths which exceed the user specified maximum combined (path + file) length.

The new Scan & Repair window tab, Max Lengths, processes only the files that exceed the specified limit.

The Shorten File Names only to Max Length option can be used to prevent shortening File Names more than absolutely necessary.

The Process only if Exceeds Max Length option can be used for the File Names, Folder Names, File Lengths, Folder Lengths and Path Lengths functions to limit processing only to the necessary file and folder names.



The Scan and Repair window was redesigned in version 4.01 to give the user greater control. The new design incorporates a tabbed interface to access the various operational modes: 

File Names - Work with characters for File Names
Folder Names - Work with characters for Folder Names
File Lengths - Work with lengths for File Names
Folder Lengths - Work with lengths for Folder Names
Path Lengths - Work with lengths for Paths

Path compression - the Path Lengths processing is new with Version 4.01. This can be used to reduce path lengths to a given target length.


The Truncation option was changed to a Shorten option which removes characters from the middle of the file name or subfolder name. For paths, the shortening is prorated based on the length of each subfolder name.


The recent change to SharePoint Online and OneDrive for Business to change the maximum number of characters from 256 to 400 gives you more flexibility with your file and folder names.


However, not all of the 400 characters are available for your use.  You need to verify the actual limit for your installation.  Please see "Max Length" and "TestSPOL" below.


Due to Microsoft's relaxing of the path + file lengths to 400 characters, the need for SharePrep and OneDriveRx has decreased.  Therefore, the prices have been reduced from $175 to $125 for SharePrep and $65 to $45 for OneDriveRx.

Assistance & Resources for Computing, Inc., has released OneDriveRx.

OneDriveRx is a limited and less expensive version of SharePrep.

OneDriveRx is limited to processing only the OneDrive, 
OneDrive for Business
and SharePoint Online "SYNC" folders and files.

[OneDriveRx Home Page]  -  click to access OneDriveRx Home Page

SharePrep is a special-purpose utility program for SharePoint that you can use to correct file and folder names in preparation for importing data into Microsoft's SharePoint Server and MOSS. The folder and filenames within SharePoint have more restrictions than for normal Windows operation.   These restrictions are for both special characters and length of the file names and folder names.

If you are seeing either of the following SharePoint messages, SharePrep can help...

The file or folder name <name> contains invalid characters. Please use a different name. Invalid characters include the following:

~ " # % & * : < > ? / \ { | }.

The name cannot begin or end with a dot and cannot contain consecutive dots.
The specified file or folder name is too long. The URL path for all files and folders must be 260 characters or less (and no more than 128 characters for any single file or folder name in the URL). Please type a shorter file or folder name.


In addition to truncation, SharePrep provides for user-defined character string substitutions which you can use to abbreviate common words in the file and folder names.  This can help you retain usable names. 


If you are seeing either of the following OneDrive messages, SharePrep can help...


   A file or folder can't be created because the path is too long  


   ...file name contains characters that aren't allowed...

...path to a file is too long... 




Download SharePrep - Utility for Renaming Files and Folders for SharePoint   Click to access download page for SharePrep

The current version of SharePrep is 5.01.

The following are the currently known File and Folder name restrictions for SharePoint:

1. The name can not contain any of the following characters:

Quotation mark
Number sign
Percent Sign
Less than Symbol
Greater than Symbol
Question Mark
Left Brace
Right Brace


2. The name can not begin or end with a period

3. The name can not contain a double period

4. The folder name and file name length depends on the SharePoint / OneDrive system used


Separate documentation for determining your maximum folder name and file name lengths is available at [Max Length].


A Free Utility is available to help determine these maximum values at [TestSPOL].

SharePrep provides a convenient user interface to allow you to search your file names and folder names for the above restrictions and provides functions for automatically renaming the file and folder names to replace the restricted characters.

SharePrep is configurable.  You can define the action to be used by the rename function for each of the restricted characters. For each, you can choose to delete the character, replace with a blank or replace with a character or string of characters you specify.

You can add additional entries to Options table.  A string of characters can be used for both the search and the replacement characters.  This gives you a means for abbreviating portions of file and folder names for the purpose of shortening their names to meet the SharePoint name length restrictions.

SharePrep provides a convenient User Interface for selecting the folder for processing, setting the Options table and Repairing the file and folder names.

SharePrep is not just for SharePoint and OneDrive.  Some customers are using SharePrep in their routine maintenance procedures to bulk rename invalid files and folders.  For example, some backup / recovery programs have name restrictions.  These customers are dealing with files downloaded from the Web and files from non-Windows systems.

The current version of SharePrep implements batch execution.  This incorporates use of a command file and provides for use of an alternate options file.

The current version also provides for user override of the 128 byte length tests.  This is to give non-SharePoint customers a means for avoiding the name length error messages.


For the File Lengths tab and the Folder Lengths tab, folder names will be shortened to the length specified in the Max Folder field and file names will be shortened to the length specified in the Max File field.


In previous versions, this was documented as a separate function,Truncate, which removed characters from the right end of the names. In the current version, the characters are removed from the center of the names which should yield more readable names.


The current version includes a function for reducing path lengths to the length specified in Max Path. The Repair function under Path Lengths performs its name reductions by attempting to remove a proportional number of characters from each level based on the number of characters available for removal.


The Resolve Duplicate Names function can be used to resolve any duplicates created by shortening, etc..  

Trial Period and Limitations

SharePrep is currently distributed only as a Limited-Trial. The rename and delete functions are available, but limited, in Limited-Trial mode.

The reason for this marketing approach is that many organizations may need SharePrep for only a single one-day conversion.  The Limited-Trial is limited to 15 days and the number of renames / deletes is limited to 50.

However, this approach permits you to use SharePrep as a diagnostic tool to check the lengths of file and folder names as well as to identify the quantity of names that require renaming.  In short, you can determine whether you need the rename functions of SharePrep before committing to the purchase of a license.  

Upon purchasing a license, you will be sent a Registration Code which you enter into SharePrep to complete the registration process. This will enable all of the program's functions.

Site Licenses

Site Licenses or Multiple-use Licenses are available for larger organizations that need them. These licenses are priced based on the number of computers that would make use of the program.  An additional 25% discount is available for Site Licenses for educational institutions, public libraries and government facilities.   [Request a Quote]


If your company requires you to fully test software prior to purchase and you are likely to purchase if you could verify that SharePrep would work on your projects and systems, Request a Trial Registration

Short Filenames

Short Filenames are the shortened version of Long Filenames that are created to fit the 8.3 format.  That is, the name is only 8 characters and the extension is only 3 characters.  The system can maintain both in its directory structure.

By default, Windows 10 is set to not create Short Filenames.  This saves a small portion of disk space.  Earlier versions of Windows were set to create Short Filenames.


As SharePrep makes use of the Short Filenames for its operations, we are asking our customers to change the Short Filenames registry setting when upgrading to Windows 10.

We are providing a free utility program Reset83.exe for checking and changing the necessary registry setting.

[ Reset83.exe ] 

Reset83.exe does not require an install.  You may execute it directly from our website or download to your computer and execute it from there.

Further, some larger data centers have transferred MAC-created files to their servers.  As MAC systems allow filenames considered invalid to Windows systems,  SharePrep may have trouble with these particularly when the invalid character occurs within the short name.

Therefore, Assistance & Resources for Computing, Inc. will refund the license fee upon receipt of proof that SharePrep is unable to perform as advertised.  Any request for a refund must be made within 30 days of the purchase.


The credit for the idea to create SharePrep belongs to Göran Husman.   He is an author, SharePoint MVP, Consultant & Trainer residing in Stockholm, Sweden.  Göran is president of HumanData Inventus AB -   He has published several SharePoint books.

Göran first requested a change in the scan function of Delete Invalid Files, to search for additional characters.  After receiving a pre-release copy of the program with the enhanced function, he requested that the program be enhanced to automatically rename files to replace the given characters.  

He explained that he had a client with a project containing over 55,000 files to be imported into SharePoint.  The scan revealed that there were over 1,000 files with restricted characters that would have to be manually modified before importing into SharePoint.

Development of SharePrep began the next day.

Assistance & Resources for Computing, Inc
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Revised: January 20, 2022