Version 5.x

Category: Installation, Version 5.x

Please check which major version of SimpleSYN Standard/Business you originally purchased.

If you purchased an older major version (e.g., version 5 or version 4), you probably have the current major version 6 installed. You can view the version number in the main window under "Information."

If this is the case:

Unfortunately, the old licenses are no longer valid for new major versions, hence the message.

Please note: Licenses are offered as a one time payment. There are no additional costs per month/year. The license entitles you to use the licensed version (e.g. version 5.0). Minor updates (eg version 5.0 to version 5.0.1 etc.) are included. Major upgrades to new versions (eg version 5.x to version 6) are subject to a fee, but optional.

If you wish to stay with your current version, first uninstall version 6. Then reinstall the major version you purchased.

You can download older major versions from the following page:
https://www.simplesyn.net/en-US/additional-downloads

After installation, your old license file will be accepted again.

Interested in version 6?

If you would like to upgrade to version 6, you will receive a 20% discount on the same number of licenses.

Simply send us an email to support@simplesyn.net with your order number and the purchase date.

Category: Troubleshooting, Version 5.x, Version 6.x

The behavior can occur if Outlook was installed in a different bit version than the previous version during the new installation. In this case, the bit versions of Outlook and SimpleSYN no longer match and SimpleSYN can no longer be started.

Uninstall SimpleSYN under the Windows control panel (or under "Apps") and then reinstall SimpleSYN.

If the behavior occurs again afterwards, then install SimpleSYN in the correct bit version as follows:

  1. First find out in which bit version (32 bit or 64 bit) Outlook was installed after the reinstallation.
    To do this, open Outlook and click on "File > Office Account > About Outlook". You can see the bit version behind the version number.
  2. Uninstall SimpleSYN from “Windows > Settings > Apps > Installed Apps”.
  3. Then download SimpleSYN and navigate to the directory where the "SimpleSYN.exe" file (for the standard version) or "SimpleSYN_Business.exe" file (for the business version) is located (e.g. on the desktop or in the download folder) .
  4. In this directory, press and hold the „shift" key on the keyboard and right click in a free area and select " Open PowerShell window here " from the context menu.

  5. After that, the Windows PowerShell window will open.

    Now type in the following command and press the ENTER key.

    Note: Pay attention to the correct spelling. There is no space at the beginning of the command between ".\".

    With the standard version:

    When you have installed Outlook in 32-Bit, use the following command:
    .\SimpleSYN.exe Platform=x86

    When you have installed Outlook in 64-Bit, use the following command:
    .\SimpleSYN.exe Platform=x64

    With the business version:

    When you have installed Outlook in 32-Bit, use the following command:
    .\SimpleSYN_business.exe Platform=x86

    When you have installed Outlook in 64-Bit, use the following command:
    .\SimpleSYN_business.exe Platform=x64

  6. You can then install SimpleSYN. After the installation, SimpleSYN is started correctly again.

Category: General, Installation, Version 5.x, Version 6.x

In the standard configuration (both in the Business and Standard versions), SimpleSYN requires an active Internet connection. SimpleSYN uses this connection to contact a central server operated by SimpleSYN, which facilitates the connection between the SimpleSYN server and the SimpleSYN client.

Only the information necessary to establish the connection is transmitted — your Outlook data is never stored in the cloud. Afterward, SimpleSYN attempts to establish a direct connection between the participating installations. The best available connection method is selected automatically.

All communication is always encrypted using SSL or TLS. Outlook data is never transmitted in plain text or permanently stored on our servers — it is only forwarded directly and securely.

Why does the Standard version also use this method?
Since most users today have an internet flat rate, we decided to use the central server in the Standard version as well — however, with the limitation that the connection is only established within the local network.

Using SimpleSYN without an Internet Connection

If you would like to use SimpleSYN without an internet connection or without our central server, then there is the option of changing the connection configuration so that our central server is no longer necessary.

Important:
This setting is primarily intended for the Standard version. In the Business version, synchronization will only work within the same local network after switching to this mode — synchronization over the internet will no longer be possible.

How to activate the custom connection (from version 5):

  1. Open the SimpleSYN main window.
  2. Go to Options > Advanced Options.
  3. On all PCs (server and clients), enable the option “Custom connection mode”.
  4. On each client, enter the computer name or the static IP address of the SimpleSYN server in the field “Custom server name/address”.

Category: General, Version 5.x, Version 6.x

First, empty the Deleted Items folder in Outlook if you no longer need the items.

Also check in the SimpleSYN main window under “Options > Advanced Options” how the “Remove backed up items” selection is set under “Backup”. If the entry is set to “never”, then set a different selection (e.g. after 14 days). Save the changes.

The SimpleSYN backup folder in Outlook is then automatically reduced in size in the background and the old backups are deleted.

Category: Troubleshooting, Version 5.x, Version 6.x

Please make a Outlook repair installation on this computer. Please follow this instruction:
https://support.office.com/en-us/Article/Repair-an-Office-application-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b

Important:

Choose a full online Outlook repair installation and NOT a quick repair.

Category: Troubleshooting, Version 5.x, Version 6.x

If SimpleSYN (Standard or Business) suddenly doesn’t start and the icon is no longer visible in the Windows taskbar, this is usually caused by an issue accessing the “SimpleSYN.config” file.

Here’s how to fix it step by step:

  1. Close Outlook if it’s currently running.

  2. Open Windows Explorer and navigate to the following folder, depending on your SimpleSYN version:

    • Version 4:
      C:\Users\[Your Username]\AppData\Local\SimpleSYN\4.0.0.0
    • Version 5:
      C:\Users\[Your Username]\AppData\Local\SimpleSYN\5.0.0.0
    • Version 6:
      C:\Users\[Your Username]\AppData\Local\SimpleSYN\6.0.0.0

  3. Locate the file named “SimpleSYN.config” in that folder.

  4. Delete this file.

  5. Restart SimpleSYN. The file will be automatically recreated.

After restarting, SimpleSYN should work normally again. You’ll just need to reactivate it once using your license file.

Don’t have your license file anymore?

No worries – simply contact the SimpleSYN Support Team to retrieve your license.

Category: Operation, Version 5.x, Version 6.x

To automatically close SimpleSYN when Outlook is closed and to start it again automatically when Outlook is started, make the following settings:

  1. Right-click on the SimpleSYN icon in the Windows notification area and choose “Exit”
  2. Close any Outlook window
  3. Open the SimpleSYN Add-In configuration file with a text editor like notepad. The configuration file can be found in:

    At Version 4:
    C:\Users\[User name]\AppData\Local\SimpleSYN\4.0.0.0\[Outlook profile name].addin.config

    At Version 5:
    C:\Users\[User name]\AppData\Local\SimpleSYN\5.0.0.0\[Outlook profile name].addin.config

    At Version 6:
    C:\Users\[User name]\AppData\Local\SimpleSYN\Add-In\6.0.0.0\[Outlook profile name].addin.config

  4. Add the following code in the section between <appSettings> and </appSettings>:

    <!-- SimpleSYN is exited when Outlook is being closed. -->
    <add key="AutoExitSimpleSyn" value="true" />
    <!-- SimpleSYN is started if the Add-In is being loaded. -->
    <add key="AutoStartSimpleSyn" value="true" />

  5. Open Outlook again.

Category: Operation, Version 5.x, Version 6.x

The SimpleSYN Business Edition can be run as a Windows service. When the option “Start as Windows service” is enabled in the advanced settings, SimpleSYN will automatically start in the background during Windows startup—without requiring a user to log in.

The SimpleSYN Standard Edition does not support this feature. In this version, synchronization only occurs when a user is logged into the computer and SimpleSYN is running.

Category: Installation, Version 5.x, Version 6.x

SimpleSYN requires a unique configuration and a unique certificate for each PC.

SimpleSYN must be completely reset to one of the clients. Then SimpleSYN can be reinstalled and set up.

Follow these steps:

  • Uninstall SimpleSYN first under the Windows Control Panel "Programs / Features" or under Apps on Windows 10
  • Then enter the following line in Windows Explorer:
    %localappdata%
  • Find the folder SimpleSYN here and delete this folder.

Then delete the SimpleSYN certificate as follows:

  • Open the Internet Explorer
  • Go to "Internet Options"
  • Click the "Content" tab
  • Click on "Certificates"
  • In the next window under "Display name" search for the SimpleSYN entries, mark the respective entry and click on "Remove"

Then you can reinstall SimpleSYN and set it up again. The initial synchronization will be run once again.

Category: Troubleshooting, Version 5.x, Version 6.x

Here's what to do if the folder list in the synchronization settings remains empty and no folders are displayed:

  1. Completely close Outlook and SimpleSYN on the affected PC.
  2. Then restart both programs.

If the issue persists, please check the following points:

Set the correct Outlook version:

  • Open SimpleSYN.
  • Go to “Options” > “Advanced Options”.
  • Under “Outlook Version”, select the version you actually have installed (e.g., Outlook 2021 or Outlook 2016).
  • Save the settings and restart SimpleSYN.

Check permissions:

  • Make sure that both Outlook and SimpleSYN are started without administrator rights.

Verify the Outlook profile:

  • In SimpleSYN, open the main menu > Options.
  • Ensure that the same Outlook profile is used as when starting Outlook.

Category: Troubleshooting, Version 5.x, Version 6.x

The message "destination folder was not found" appears if the top folder level in Outlook (eg "Personal folders") has been named differently on the SimpleSYN client and SimpleSYN server. In this case, SimpleSYN can not assign the destination folders automatically because no new PST files are created by SimpleSYN.

Click on the "Select a different target folder" link and select the folder where you want to sync.

Alternatively, you can name the highest folder level identically on all computers in advance.

Category: Installation, Version 5.x, Version 6.x

You can easily upgrade Outlook to a newer version – there's no need to uninstall the previous version. SimpleSYN will automatically detect the new Outlook version.

Important:
Make sure to install Outlook in the same bit version as before – either 32-bit or 64-bit.

If you want to install Outlook in a different bit version than the previous one, please follow these steps:

  1. First, uninstall SimpleSYN.
  2. Then, update Outlook.
  3. Finally, reinstall SimpleSYN.

Category: General, Version 5.x, Version 6.x

How to remove an old Client PC from the Server PC in SimpleSYN:

  1. Open the SimpleSYN main window on the server PC.
  2. Press the Alt key to display the menu bar.
  3. In the View menu, click on Status Properties.
  4. Switch to the General tab.
  5. In the list, find the entry for the old PC or user you want to remove.
  6. Select the corresponding entry and click Remove.

Category: Operation, Version 5.x, Version 6.x

To call up the Configuration Wizard again, please follow these steps:

  1. Open the SimpleSYN user interface
  2. Press the “Alt“ key to show the SimpleSYN menu 
  3. In the menu under “Help” activate the entry “Show Configuration Wizard on next startup“
  4. Exit SimpleSYN. To do so right-click on the SimpleSYN symbol in the Windows system tray and choose “Exit”

The next time SimpleSYN is opened the configuration window will be displayed again.

Category: Troubleshooting, Version 5.x, Version 6.x

If you have made changes to the Outlook default color categories, you must ensure that the color category list (formerly the "Main Category List") is manually configured identically on all PCs. SimpleSYN does not automatically synchronize this list. The categories assigned to the items are retained and correctly synchronized by SimpleSYN.

Starting with version 6, the "Add new categories to the main category list" function is available.

If this option is enabled, SimpleSYN checks during synchronization whether all categories used in the items are also present in the main category list. If a category is missing, it is automatically added to the list with a default color. You can then manually adjust the color to ensure a consistent display across all devices.

Category: Installation, Version 5.x, Version 6.x

An active internet connection is required for synchronization using SimpleSYN Business and SimpleSYN Standard.
SimpleSYN uses this connection to contact a central server operated by SimpleSYN, which facilitates the connection between the SimpleSYN server and the SimpleSYN client.

Only the information necessary to establish the connection is transmitted — your Outlook data is never stored in the cloud. Afterward, SimpleSYN attempts to establish a direct connection between the participating installations. The best available connection method is selected automatically.

If a computer using the SimpleSYN Business version is to be synchronized over the internet, but a direct connection between the SimpleSYN server and client cannot be established — for example, due to firewalls, routers, or NAT — SimpleSYN will use a relay server as a last resort. This allows communication even in networks where only outbound traffic is permitted.

All communication is always encrypted using SSL or TLS. Outlook data is never transmitted in plain text or permanently stored on our servers — it is only forwarded directly and securely.

Note: 
Proxy server support is available starting with SimpleSYN version 5. For older versions, access to our servers at services.simplesyn.net must be explicitly allowed.

SimpleSYN requires the following outbound TCP connections.

DNSIP-AddressPorts
Version 6 and version 5:
SimpleSYN
Server & Clients		 services.simplesyn.net
services2.simplesyn.net
Relay connections (Turn Server)		 20.113.6.16
20.113.6.17
20.113.6.16/29		 443
443
49152 – 59152
Version 4:
SimpleSYN
Server		 services.simplesyn.net
services2.simplesyn.net		 20.113.6.16
20.113.6.17		 9235, 9236,
3478
SimpleSYN
Clients		 services.simplesyn.net
services2.simplesyn.net
Relay connections (Turn Server)		 20.113.6.16
20.113.6.17
20.113.6.16/29		 9235, 9236
3478
49152 – 59152