When transferring project data from Microsoft Project to Replicon's Timesheet, once the transfer is completed you get a prompt to save changes to the Resource Pool even though no data was transferred from Timesheet to MS Project.

When you open both a resource pool and a project sharing resources contained in that resource pool, the process of connecting the two files in memory updates internal fields in each file. Although you are not able to see these changes, Microsoft Project notes them and prompts you with the Save Changes dialog box.
In addition to the internal fields, the resource information is synchronized between the two files.
For example, if the Pool and Share files have the same resource, R1, but one file has a standard rate of $5.00/h and the other a standard rate of $6.00/h, these differences have to be resolved so that the two files can share the resource. Since the resource synchronization occurs each time the files are opened, the files needs to be saved. As far as the integration manager is concerned no changes are made to the .mpp file and its safe to click Yes to All after a transfer is completed.