This could be for a variety of reasons.
If this affects a single user, and is a standard tab (such as debtors of creditors) the most likely cause is that the security profile they are registered to has had permissions removed for the module in question, and we would suggest that you check the profile for a working user against a non-working user - please see our article on managing security profiles for information on this.
If the module missing is part of the plug-ins for Dimensions, and the user has recently had a new installation or PC, t is usually as a result of your original installation of Dimensions being copied to your new Windows environment. While Dimensions will work, the plug-ins will not be activated on your system. You can re-activate them using the following process (note that you may need assistance from your IT department to carry out this operation):
Log out of Dimensions
Navigate to the installation of Dimensions on your machine (this is usually C:\Program Files (x86)\Access Applications\Dimensions\Accounts\your version of Dimensions
Open the CustomService folder
You should have a file here that begins Applied_Custom_Plugins
Right click the file and select Rename
Remove the Applied_ from the beginning of the file name (so the file name begins Custom_Plugins)
Log into Dimensions
At this point the custom plugins file should be applied to Dimensions, which will activate and enable your plugins
If the Custom_plugins file does not exist, you may need to install the plug ins on your system. Please see our article on installing plug-ins for information on this.