Best Practices for a File Share to SharePoint Migration

Analyze the Source file shares

Prior to migration, a full analysis of each file share should be made. The following third-party tools can assist with this:

These third-party tools are recommended within the community, but they are not owned and managed by BitTitan. Always do your own due diligence before running any third-party tool against your environment.

If there is data that is no longer required, back it up and remove it from the file share or simply do not include it in the migration.

Evaluate the amount of data under each file share. When migrating to SharePoint Online, you should be aware of the current limits. Details of these can be found in the Microsoft article, SharePoint Online limits. One of the most important limits to be aware of is that there is a sync limit of 5,000 items in site libraries, including files and folders. This means that you can view only up to 5,000 items in site document libraries or lists. To view anything more than this, see Manage large lists and libraries in Office 365.

Information from this article:

Before you migrate files and lists to SharePoint Online, consider the list view threshold. Often, you might need to reorganize your files, or rethink your lists before you migrate, to make them work smoothly in Office 365.

  • Libraries: Analyze your current files. Think about how much of the content is used regularly, and whether you want to store all of it in Office 365. In Windows Explorer, search your files by size and by date to quickly identify the large or recent files. You can reorganize the files into folders so that no single folder exceeds the List View Threshold. Organize content into folders by topics or categories. For example, organize contracts into folders based on the month that the contract was signed, invoices based on the creation date, or files into custom categories that correspond to your business.
  • Lists: It is also possible to create folders in a list, but there is no easy way to move list items between folders, as you can with libraries. Consider splitting large lists into multiple lists so that no list exceeds the List View Threshold. In some cases, this strategy works well when there is a practical way to subdivide the data that makes sense to users. If splitting into lists is not practical, migrate a portion of the data to the list below the List View Threshold.

For optimal migration speeds, and to keep your SharePoint site libraries at a manageable level, we recommend restructuring your Source file shares, prior to migration. Each file share should be restructured so that it does not contain more than 1,000 items.

Increase the MigrationWiz InitializationTimeout parameter

For large file share migrations, we recommend increasing the MigrationWiz InitializationTimeout Advanced Option parameter. By default, MigrationWiz allows one hour to initialize the migration but, depending on the number of existing folders, this may take much longer

The best solution is to increase the timeout by using the Advanced Support Option InitializationTimeout. This value is in hours, up to a maximum of 100 hours.  Values above 100 are in milliseconds. For example:​
  • InitializationTimeout=2 will increase the timeout to 2 hours.
  • InitializationTimeout=4 will increase the timeout to 4 hours.
  • InitializationTimeout=6 will increase the timeout to 6 hours.
  • InitializationTimeout=8 will increase the timeout to 8 hours.


  • InitializationTimeout=7200000 will increase the timeout to 2 hours.
  • InitializationTimeout=14400000 will increase the timeout to 4 hours.
  • InitializationTimeout=21600000 will increase the timeout to 6 hours.
  • InitializationTimeout=28800000 will increase the timeout to 8 hours.
To be safe, it is easiest to just set this to 8 hours or more.

Review how permissions are handled

Here is a breakdown of how permissions are handled during the migration:

  • Permissions will be applied to the individual files and folders, not to the lists.
  • Permissions are not applied at the Groups level within SharePoint.
  • Permission mappings are applied to translate NTFS permissions over to their SharePoint equivalent. For example, NTFS edit permission is translated to SharePoint contribute permission.
  • SharePoint site, list, and personal permissions should be set up post-migration.
  • Permissions are migrated using the Source AD UPN. In order to be able to migrate these, the same user accounts must exist on the Destination Office 365 tenant.

Decide on a strategy to follow when uploading file shares to Azure container(s)

The optimal approach to take will be dependent upon your file share structure and whether or not you want to migrate permissions.

Scenario 1: Migrating several small file shares to SharePoint Online, and migrating permissions.

When migrating several small file shares to SharePoint Online, and migrating permissions, the best practice is to upload each file share to a separate container in Azure. You will then create a separate MigrationWiz document migration project per Azure container.

Then, when adding each line item within MigrationWiz, you will not need to apply any filters because each container holds only the data that will be migrated to each SharePoint site library. You will, however, have to change the name of the container, within each MigrationWiz project, so that it reflects the name of your Azure container.

We advise this approach because if you add all file shares to the same container, and then apply filters to each line item so that only the data for each file share is migrated into the corresponding SharePoint site library, then these filters do not apply to permissions. MigrationWiz would then try to apply permissions to every file and folder that it finds in the Azure container. For all those files and folders that do not exist on the Destination SharePoint site library, MigrationWiz will log an error. This will slow down the migration, and will also cause it to fail, once it reaches the maximum number of errors per migration count (as defined within the project's Advanced Options).

Scenario 2: Migrating several small file shares to SharePoint Online, and not migrating permissions.

If migrating several small file shares to SharePoint Online, and not migrating permissions, then you could just upload all file shares to one container. You could then create just one MigrationWiz document migration project, and apply filters to each line item. This way, when migrating, it will filter out all the other file shares and only migrate the data within each file share to its corresponding SharePoint Site library.

  • Click Add, then enter the name of the document library. The name of the document library is the one in the URL. For example, if the name of the document library is "Documents", but in the URL it says Documents/, the name is Shared Documents.
  • If you do not customize the migration line by applying a folder filter, all the documents that are uploaded into your Azure container will be migrated into this document library.
  • If there is a single folder and all its subfolders and documents are to be migrated, edit the migration line and add a user. For guidance, see View, Add, and Edit Customer's Users. This will add two metadata files to the Azure container. These are used to capture the directory structure and permissions, from the Source.
  • The admin account that is being used for migration (by MigrationWiz) will need to have read access to all file shares.

Set the Source file shares to read-only, during migration (after UploaderWiz has completed the upload to Azure).

Once the upload has completed, then you can set the Source file share to read-only.

Important: Do not do this step until after the upload has completed. UploaderWiz needs to capture the permissions from the Source in order to be able to migrate them, so you must not set these to read-only before UploaderWiz is run.

Set MigrationWiz Advanced Options to overcome SharePoint Online limitations and to increase the amount of data that can be migrated in one pass

At the MigrationWiz project level, add these Advanced Options, under Support/Support options:

At the individual item level, add folder mapping so that folders map to the root folder. If you do not add this folder mapping then the default is to create a subfolder under the root folder, with the name of the file share.

Example mapping:


More details can be found in Can I add folder mapping in MigrationWiz?.

Decommission Source file shares, post-migration

This step is recommended to ensure that users begin to use SharePoint Online, post-migration. We also recommend running a full backup against all file shares, prior to deleting any files.

You can either completely remove the file shares, or delete all files within the shares. If choosing the latter option, you could leave one file within the file share. This file could be a small "read me" text file that explains that the file share has been moved to SharePoint Online. This file could include instructions to connect to SharePoint Online, and a link to a video on how to use SharePoint Online.

Provide SharePoint Online training to users, and make sure they can access the SharePoint site libraries, post-migration

The Microsoft TechNet section, SharePoint for IT pros, is a useful resource for new SharePoint Online users.

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