I have a situation where we moved hosted servers 3 weeks ago.  We did backup and restore and just found out last week that the attachments were not manually copied over to new server.  So now we have new attachments that can be viewed but the old attachments can not be viewed.  I have read about the 

What you need to do is reattach the files by going to Doc Center. Here's how:

1. Browse to the location where your company file is stored.Default location: C:\Users\Public\Public Documents\Intuit\QuickBooks\Company Files
2. Make a new Attach folder.
   a. Rename Attach folder by adding "_OLD" to it.
   b. Create a new folder and name it Attach.
3. Copy the contents from the old folder.
   a. In the new Attach folder, create a folder that matches the name of the company file. Open the new folder.
   b. Create new sub-folders named Inbox and TXN.
   c. Copy and paste contents over to respective new folders from their old counterparts.
4. From the QuickBooks Company menu, select Documents > Repair Attached Documents Links.
5. Select Repair Links.

If I copy the old attach folder(Inbox and TXN) contents into the newer attach folders and do a repair will it merge both new and old attachments