Thank goodness I found this post. 

We are experiencing the exact same thing using maxshipper for a client of ours. I replaced the clients entire server just to rule it out. I know this post is 6 months old but have you found a solution to this? Any insight you can provide? 

Yeah it is very difficult to troubleshoot this (hence it took us 4 months to get it right).

Did you replace the client's entire server and started off on a new configuration or did you just replicate the same configuration on new hardware? The latter will not work.

It seems the Sage data path folder that was originally mapped to had some permissions issues (or some kind of restrictive policies) that I couldn’t really determine for sure. People before me configured the server and they were some extra paranoid folks. So I just created a new data path, set more relaxed permissions on the folder, uninstalled Sage and re-installed Sage again mapping to the new data path during the installation phase.

Detailed steps below:

1. Uninstall all previous Sage versions from the server and client PC where MaxShipper will be installed. Just have the latest version you are using only. [Not sure this matters but do it anyway]
2. Remove all unused backup companies that are not being used. These companies must also be removed from Sage Company folders in all data paths – especially if they are sharing the same name.
3. Uninstall latest Sage that is being used.
4. Reboot PC.
5. Re-install Sage and create a new data path in the process.
6. Redo share permissions on the new data path folder for network access BUT make it less restrictive. For example, for Share permissions, select “Everyone” for now to make sure everyone has full control over the folder temporarily.
7. Copy company folder from the previous data path into the new data path (don’t delete the previous copy yet).
8. Open new Sage instance, activate and then test to make sure you can open the company in the new data path.
9. Recheck all data is there as is.
10. Close Sage.
11. Delete previous copy of the Company folder in the old data path. (You can keep the old data path as is).
12. Reconfigure MaxShipper to map to new data path.
13. Test Company/Data on MaxShipper. Make sure company and data are loading instantly.
14. Once successful, restrict folder share permissions in #5. Retest MaxShipper each time new restrictions are placed.
15. At some point, if MaxShipper does the same thing again (i.e takes long to load company/data), it means that a certain restriction/policy on the folder is limiting access. Find contingencies or decide not to use that policy.

I would suggest to create a backup image of the server and restoring it on another server PC. Then put the PC in a sandbox network configuration consisting of one server PC and client PC (where MaxShipper is running). Then do these tests so that you don’t break the actual server (if it is still being used). After the test is successful, to replicate the same procedure on the main server (which is what I am going to do next).

Yeah it is very difficult to troubleshoot this (hence it took us 4 months to get it right).

Did you replace the client's entire server and started off on a new configuration or did you just replicate the same configuration on new hardware? The latter will not work.

It seems the Sage data path folder that was originally mapped to had some permissions issues (or some kind of restrictive policies) that I couldn’t really determine for sure. People before me configured the server and they were some extra paranoid folks. So I just created a new data path, set more relaxed permissions on the folder, uninstalled Sage and re-installed Sage again mapping to the new data path during the installation phase.

Detailed steps below:

1. Uninstall all previous Sage versions from the server and client PC where MaxShipper will be installed. Just have the latest version you are using only. [Not sure this matters but do it anyway]
2. Remove all unused backup companies that are not being used. These companies must also be removed from Sage Company folders in all data paths – especially if they are sharing the same name.
3. Uninstall latest Sage that is being used.
4. Reboot PC.
5. Re-install Sage and create a new data path in the process.
6. Redo share permissions on the new data path folder for network access BUT make it less restrictive. For example, for Share permissions, select “Everyone” for now to make sure everyone has full control over the folder temporarily.
7. Copy company folder from the previous data path into the new data path (don’t delete the previous copy yet).
8. Open new Sage instance, activate and then test to make sure you can open the company in the new data path.
9. Recheck all data is there as is.
10. Close Sage.
11. Delete previous copy of the Company folder in the old data path. (You can keep the old data path as is).
12. Reconfigure MaxShipper to map to new data path.
13. Test Company/Data on MaxShipper. Make sure company and data are loading instantly.
14. Once successful, restrict folder share permissions in #5. Retest MaxShipper each time new restrictions are placed.
15. At some point, if MaxShipper does the same thing again (i.e takes long to load company/data), it means that a certain restriction/policy on the folder is limiting access. Find contingencies or decide not to use that policy.

I would suggest to create a backup image of the server and restoring it on another server PC. Then put the PC in a sandbox network configuration consisting of one server PC and client PC (where MaxShipper is running). Then do these tests so that you don’t break the actual server (if it is still being used). After the test is successful, to replicate the same procedure on the main server (which is what I am going to do next).

So I did just image from the old server to the new hardware so yes the config would all be the same which is why new server hardware didn't fix it because its not hardware related. We now have this resolved as well but we did not do your method. 

We had another VM virtualized on this server. We did a fresh install of sage and did a backup / restore to the other server. Maxshipper was very helpful with testing along the way before we did the actual cut over. 

They reached out to me with a couple of other clients of theirs having the same issue with sage. I have supplied them with this article and your very detailed response in hopes it can help others. 

Thank you again!