You've covered so much. If it is happening with multiple workstations then it must be an issue with program files on the network. Perhaps try installing program files locally and eliminate that possibility. Alternatively (or in addition too) set up a DEP exception for accpac.exe.

Check the PATH for multiple references to the Runtime folder.

Assumptions - please read carefully and *let us know any that are, or might be, incorrect*:
1. There is a domain controller.
2. The server and client machines are all connected to this domain controller via ethernet.
3. You are using an administrative account with is a member of the Domain Admins group, or the Local Administrators group on the ERP Server and all Client machines (have the IT Vendor physically show you to be absolutely certain).
4. Programs and Shared Data are both installed on a Windows Server 2008 machine (not a Windows Server 2008 "R2" machine).
5. Programs and Shared Data directories are shared via [directory] > properties > sharing, and permissions are correctly set.
6. Programs and Shared Data permissions are correctly set via [directory] > properties > security tab, with a minimum or Read access on the Programs directory, and Read/Write access on the Shared Data directory.
7. All errors are immediately reproducible, and in no way intermittent.

Suggestions, in addition to the others, to be run on the client machines:
1. If UAC is enabled, then disable it (set to "Never"), reboot, then reinstall workstation.
2. Run Regacc by right clicking Regacc.exe and clicking 'Run as Administrator', then check C:\Windows\Regacc.log (or wherever it is output) and confrim that all registrations were successful.
3. Run Accpac by right clicking Accpac.exe and clicking 'Run as Administrator'.
4. Double check that all Firewalls are disabled - there could be several installed, on the Client OS, Server OS, Router etc.
5. Double check that all AV/Malware/Security software are disabled - there could be several installed on the Client OS, Server OS, or another machine connected to the domain (isolate the ERP Client and Server machines at the network level to be absolutely certain).
6. Check with the system administrator that no further security measures have been put in place (login scripts, AD Group Policy, Local Security Policy etc.)
7. Run sysinternals' Procmon.exe (Process Monitor) and filter on Accpac.exe etc. (compare to procmon on server if required, and isolate differences)
8. Plug your own known-good computer into the network and test the workstation install.
9. Let us know exactly what you have tried, and exactly what results you experienced (provide links to screenshots via Google Drive etc. if that is easier for you).

*If you get this resolved, please let us know what the solution was (to help other partners in the future).*

Good hunting.

Only one path statement

I think the best way to respond to this one is

1. there is a domain controller.------- Correct

2. The server and client machines are all connected to this domain controller via ethernet. --------Correct

3. You are using an administrative account with is a member of the Domain Admins group, or the Local Administrators group on the ERP Server and all Client machines (have the IT Vendor physically show you to be absolutely certain). -------Rechecked

4. Programs and Shared Data are both installed on a Windows Server 2008 machine (not a Windows Server 2008 "R2" machine). --------Windows Server 2008 R2

5. Programs and Shared Data directories are shared via [directory] > properties > sharing, and permissions are correctly set. --------Correct

6. Programs and Shared Data permissions are correctly set via [directory] > properties > security tab, with a minimum or Read access on the Programs directory, and Read/Write access on the Shared Data directory. ------- Correct

7. All errors are immediately reproducible, and in no way intermittent. ---------- Correct

Suggestions, in addition to the others, to be run on the client machines:

1. If UAC is enabled, then disable it (set to "Never"), reboot, then reinstall workstation. ------- UAC Disabled

2. Run Regacc by right clicking Regacc.exe and clicking 'Run as Administrator', then check C:\Windows\Regacc.log (or wherever it is output) and confrim that all registrations were successful. --------Have done this a couple times as per initial post

3. Run Accpac by right clicking Accpac.exe and clicking 'Run as Administrator'. ------- I always do that

4. Double check that all Firewalls are disabled - there could be several installed, on the Client OS, Server OS, Router etc. - -------- No firewall enabled

5. Double check that all AV/Malware/Security software are disabled - there could be several installed on the Client OS, Server OS, or another machine connected to the domain (isolate the ERP Client and Server machines at the network level to be absolutely certain). --------all antivirus/Malware/security software at first disable then completly uninstalled

6. Check with the system administrator that no further security measures have been put in place (login scripts, AD Group Policy, Local Security Policy etc.) -------- non in place

7. Run sysinternals' Procmon.exe (Process Monitor) and filter on Accpac.exe etc. (compare to procmon on server if required, and isolate differences) ------ No issues

8. Plug your own known-good computer into the network and test the workstation install.-------------Own pc run Sage local without issue , have logged on to domain and same issue appear

9. Let us know exactly what you have tried, and exactly what results you experienced (provide links to screenshots via Google Drive etc. if that is easier for you).

more info

Have uninstalled and reinstall from new ISO ------same issue

Client was on v6.1 and was just an upgrade ----- have reinstalled v6.1 and system works 100 %

I'm not at client site anymore and cannot do screenshots (3 hours flight from Office)

Temp measure Users is logging in to remote desktop and process (on 2016 install )------- not viable long-term solution.

I have exhausted most solutions i could think of.

Regards

Philip

One other "straw" to grab at is to disable UAC (not just lowering it to the bottom level):

Registry (proceed carefully).
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System
EnableLUA set it to 0 (should be at 1)
Reboot required

Hi Phil,

Thanks for taking the time to respond in detail - this probably sounds like an endless, and tiresome, list of questions but these are the same steps I go through when I'm faced with these challenges (of which there have been many, over the years).

You mention there are "no issues" in the Procmon output, but I suspect the Procmon log output immediately after the logo is displayed (but before the signon screen fails to load and the 'app crash' is encountered) has some useful information.

Suggestions:
10. Get remote access via TeamViewer (if possible).
11. I'm sure you're aware, but Sage dropped support for Windows Server 2008 R2 under Sage 300 2016 (regardless of 300C), for some absurd reason. That said, I recently read a post on this forum that said Server 2008 R2 works fine so long as you are not running web screens (or something along those lines). Please advise if you installed the Web Screens during installation on the Server.
12. Advise if any client is working (it's not entirely clear to me from your original post, as you mention "on some workstations"). If at least one client is working, compare the installed programs between good and bad clients and advise any differences.
13. Try and convince your Customer to provide remote access via TeamViewer.
14. Run Sysinternals' Process Explorer on both the client and the server, reproduce the issue, then advise if you see anything strange.
15. Run Procmon on both the client and the server, reproduce the issue then, with the clients permission, upload the Procmon output (.PML) from both machines, plus the Eventviewer logs from both machines, to Google Drive etc. and provide a link.