Dear Community,I am writing you all because in my Company we have massive Issues with FortiClient (EMS) on the macOS Clients. I am working as IT Administrator and I am responsible for the MacBook’s.The problem:On the Mac Devices we have since many months the problem that when connected with the VPN the Download Speed is extremely low. We have an External Internet Connection at Work with 100 Mbit/s. With WiFi i get WITHOUT VPN like 80-100 Mbit/s. With VPN ON i get like 5 to 10 Mbit/s (with LAN connection it’s a little bit better). There were also days where it was more so its really inaccurate. The Upload Speed is the same with VPN ON and OFF. ~ 40 Mbit/s. For Windows VPN OFF and VPN ON is the same Download Speed. Some informations:EMS Policies are the same for the Windows- and the macOS Clients We have this features: Remote Access (SSLVPN with Split Tunneling, Webfilter and Vulnerability Scan) Windows Devices are still on 7.2.14 and macOS Devices are on 7.4.5 (I also tested today 7.4.7 the newest but same problems and also with 7.2.X we have the same problems) The Mac’s are supervised with JAMF Pro. FortiClient Configuration Profile is used and properly configured. All MacBooks are on macOS 26 I tested so much on my Client but it was always the same result. Sadly I never got an improvement. For EMS site i can’t to anything because another Department takes care of that. I would gladly appreciate some solutions. If more informations are needed please let me know and thank you all! Best regardsAdrian

Hi AdrianIn your case I’d try 2 troubleshooting ways:Change the enc-auth pair to something like aes128-sha256Modify the MTU size using the <mtu_size> XML option to 1300, 1280 or even lessHope it helps.

A

AdrianMOP

New Member

Question

Issues with FortiClient (EMS Version) on macOS

Forum|Forum|23 days ago
July 20, 2026
5 replies
157 views

Dear Community,

I am writing you all because in my Company we have massive Issues with FortiClient (EMS) on the macOS Clients. I am working as IT Administrator and I am responsible for the MacBook’s.

The problem:

On the Mac Devices we have since many months the problem that when connected with the VPN the Download Speed is extremely low. We have an External Internet Connection at Work with 100 Mbit/s. With WiFi i get WITHOUT VPN like 80-100 Mbit/s. With VPN ON i get like 5 to 10 Mbit/s (with LAN connection it’s a little bit better). There were also days where it was more so its really inaccurate. The Upload Speed is the same with VPN ON and OFF. ~ 40 Mbit/s.
For Windows VPN OFF and VPN ON is the same Download Speed.

Some informations:

EMS Policies are the same for the Windows- and the macOS Clients
We have this features: Remote Access (SSLVPN with Split Tunneling, Webfilter and Vulnerability Scan)
Windows Devices are still on 7.2.14 and macOS Devices are on 7.4.5 (I also tested today 7.4.7 the newest but same problems and also with 7.2.X we have the same problems)
The Mac’s are supervised with JAMF Pro. FortiClient Configuration Profile is used and properly configured.
All MacBooks are on macOS 26

I tested so much on my Client but it was always the same result. Sadly I never got an improvement. For EMS site i can’t to anything because another Department takes care of that. I would gladly appreciate some solutions. If more informations are needed please let me know and thank you all!

Best regards

Adrian

Stephen_G

Staff & Editor

Hi AdrianMOP,

Thanks for using Fortinet Community. We’ll look to get you an answer or help. In the meantime, if anyone else has any advice, feel free to respond.

Stephen_G - Fortinet Community Team

AEK

SuperUser

Hi Adrian

In your case I’d try 2 troubleshooting ways:

Change the enc-auth pair to something like aes128-sha256
Modify the MTU size using the <mtu_size> XML option to 1300, 1280 or even less

Hope it helps.

AEK

A

AdrianMOPAuthor

New Member

Dear @AEK

thank you for answering my question. So for the MTU we already have 1300. We also now implemented DTLS but it also didn’t change anything and that was my last idea. For the Encryption is this on EMS site? Because I can’t do there anything. We have a Network & Infrastructure Team for that. Could you explain it to me a little bit more? Many thanks in advance.

Kind regards,

Adrian

AEK

SuperUser

Hi Adrian

You can still try MTU 1280.

Regarding enc-auth pair, you do it on both FGT IPsec tunnel config and on EMS VPN profile. They must match.

AEK

A

AdrianMOPAuthor

New Member

Dear @AEK,

with the MTU change nothing really changed. We don’t use IPsec, we use SSL VPN. But we found maybe something. We tried FortiClient WITHOUT EMS and got like 80mbps. Then with EMS it was only 20mbps. We think the Webfilter could interfere. Because on macOS the Webfilter works directly as Extension and it could interfere. Our biggest problem is with the SMB. We have a Windows Server with Network Shares. With FortiClient on it is soooo slow. Even connecting takes long and then opening a files often freezes the Finder.

BR

Adrian

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