Category: Troubleshooting, Version 4.x, Version 5.x

Please make a Outlook repair installation on this computer. Please follow this instruction:

Important: choose a full online Outlook repair installation and NOT a quick repair.

Category: Troubleshooting, Version 4.x, Version 5.x

In this case there is an problem on the file "SimpleSYN.config", so SimpleSYN can not be started anymore.

To repair SimpleSYN on this computer, please follow these steps:

  • Open a Windows Explorer and navigate to this directory:

    For Version 4:

    For Version 5:

  • In this directory you will find the file: “SimpleSYN.config” (may also be shown as just “SimpleSYN” without the extension .config).
  • Delete this file
  • Restart SimpleSYN

Then SimpleSYN starts normally again. You would then need to activate SimpleSYN only once with your license file.

If you no longer have the license, contact our support.

Category: Troubleshooting, Version 4.x, Version 5.x

Close Outlook and SimpleSYN on the PC and then restart both applications.

If the behavior persists after that, check the following points:

  1. Select the right Outlook version in SimpleSYN under Options -> Advanced Options under “Outlook version”. Save the settings and restart SimpleSYN again.
  2. Make sure neither Outlook nor SimpleSYN is started with administrator rights..
  3. Check if SimpleSYN and Outlook are using the same Outlook profile. You can see the Outlook profil in SimpleSYN in the main window > Options.

Category: Troubleshooting, Version 4.x, Version 5.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: Troubleshooting, Version 4.x, Version 5.x

Open the SimpleSYN options > advanced options and under “Outlook version” select your current Outlook version (2016 or 2013).  Save the settings and restart SimpleSYN.

If the behavior still occurs:

  • Please uninstall SimpleSYN on this computer from the Windows control panel > program/features and install SimpleSYN once again

If the behavior still occurs:

Category: Troubleshooting, Version 4.x, Version 5.x

Duplicate e-mails can occur on an POP3 account, when e-mails from more than one computer being synchronized are requested from the e-mail server. This is the case if the Outlook function “Leave copy of messages on the server” was activated in a POP3 E-mail account.

The tricky here is that SimpleSYN cannot force Outlook to stop downloading an email a second time on another computer. If the first computer downloads the mail from the email server and it gets synchronized before the second computer downloads it, Outlook cannot detect that the email is already there. The second computer will than download the email from the email server and you got a duplicate. As the first email is also already synchronized, SimpleSYN assumes that the second download is intentional and synchronizes this copy too.

In this case deactivate the Outlook function “Leave copy of messages on the server” so as not to save e-mails in your mail server and download them repeatedly.

To deactivate this function follow these steps:

  1. Open Outlook
  2. Open the Backstage area by clicking on “File“
  3. In the category “Information” click on “Account Settings” and “Add or Remove Accounts…”
  4. Highlight the POP3 E-mail account in question and click on “Change“
  5. Click on “More Settings“
  6. In the tab “Advanced” deactivate the check box “Leave copy of messages on the server“
  7. Confirm the changes by clicking “OK“
  8. Click on “Next“ and then on “Finish“

Category: Troubleshooting, Version 4.x, Version 5.x

If SimpleSYN cannot establish a connection make sure the following is correct:

  1. Make sure SimpleSYN is installed and started on both the client and the server computer
  2. At least one computer has to be configured as SimpleSYN server and a second as SimpleSYN client
  3. Install the latest version of SimpleSYN on all computers that are to be synchronized
  4. Make sure you have an active internet connection on both computers
  5. Check whether the time is correctly set on both computers. Set the same time on both computers.


  1. Make sure the correct server has been selected on the SimpleSYN clients.
  2. Make sure the password has been entered correctly.

Category: Troubleshooting, Version 5.x

Open the SimpleSYN main window> Options> advanced options on the PC.

Check the box next to "Enable Outlook Add-In" and save the page.

Then restart SimpleSYN.

Otherwise, check once in Outlook under File> Slow and deactivated COM add-ins whether in this area the add-in has been deactivated and reactivate the add-in if necessary.

Category: Troubleshooting, Version 3.5, Version 4.x, Version 5.x

This message can be triggered by flawed Add-Ins from Third Party manufacturers. Outlook Add-Ins from Third Party manufacturers can hinder communication between SimpleSYN and Outlook.

Known problems: You may receive this message if you have the Apple Mobile Device Support Add-In installed, which is automatically installed by iTunes. The Add-in may make the PST file unusable for other applications when Outlook is shut down. Then SimpleSYN will also no longer be able to access the PST file.

To avoid the problem do not close Outlook while SimpleSYN is running.

If you are not using iTunes to synchronize an iPhone/iPod with Outlook, you could also deactivate the Add-in in Outlook.