Updating all contacts from Google to Outlook every sync

Sync Outlook contacts and calendars with Google

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#1028 Updating all contacts from Google to Outlook every sync

Status: pending

Owner: Florian Saller

Labels: Syncing problem (1)

Updated: 2026-04-04

Created: 2025-04-23

Creator: TA

Private: No

GO Contact Sync Mod (4.2.1)
Windows 11 Home Premium Edition (Build 26100) (64-bit) (Release ID 24H2)
Outlook (new) 365
Using with Gmail

Every time an auto sync is run, it is updating all 2077 contacts despite nothing having changed. Is this a bug, or is there some way to skip contacts that are static? I saw some reports of downgrading back to 4.1.33 as a fix, is this the recommended resolution? Photo attached. Thank you

1 Attachments

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Discussion

TA - 2025-04-23

Just to provide an update, I downgraded to 4.1.33 as recommended by another user and the initial sync did run shockingly fast compared to 4.2.1. However, I started a second manual sync just to ensure everything was working properly and it started syncing very slowly again. Please see attached for a photo. I have no idea how to fix this, so any input would be greatly appreciated. Thank you

Untitled.png

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Richard Austin - 2025-10-17

I have the same issue. It now sync's all contacts on every sync, even though no change to the contact was made.
Additionally, I have 253 Google contacts, yet it showed only synced 68 of the 253. As a test I updated all 253 Google contacts by opening each and making a minor change with save. After that it synced 250 of 253.
The next day I went to see if I could identify what 3 are missing from the sync and it now shows only 67 are being synced.
Is there a logging mode I can set to help identify why it continues to sync 67 of 253 when no change is made to that contact.

Example: 2025-10-17 06:26:26 | Information | Sync complete. Synced: 67 out of 253. Deleted: 0. Skipped: 0. Errors: 0.

Here is the actual output (With names Redacted)

2025-10-17 06:25:14 | Information | Sync started (Google to RDRedacted).
2025-10-17 06:25:14 | Information | Connecting to Google...
2025-10-17 06:25:14 | Information | Connecting to Outlook...
2025-10-17 06:25:14 | Information | Loading Outlook contacts...
2025-10-17 06:25:14 | Information | Loading Google Groups...
2025-10-17 06:25:14 | Information | Loading Google Contacts...
2025-10-17 06:25:14 | Information | Removing Outlook duplicated contacts...
2025-10-17 06:25:17 | Information | Removing Google duplicated contacts...
2025-10-17 06:25:18 | Information | Matching Outlook and Google contacts...
2025-10-17 06:25:26 | Information | Syncing groups...
2025-10-17 06:25:26 | Information | Syncing contacts...
2025-10-17 06:25:28 | Information | Updated contact from Google to Outlook: "BRedacted".
2025-10-17 06:25:29 | Information | Updated contact from Google to Outlook: "DRedacted".
2025-10-17 06:25:30 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:25:30 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:25:31 | Information | Updated contact from Google to Outlook: "GRedacted".
2025-10-17 06:25:32 | Information | Updated contact from Google to Outlook: "LRedacted".
2025-10-17 06:25:32 | Information | Updated contact from Google to Outlook: "LRedacted".
2025-10-17 06:25:33 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:25:34 | Information | Updated contact from Google to Outlook: "TRedacted".
2025-10-17 06:25:35 | Information | Updated contact from Google to Outlook: "BRedacted".
2025-10-17 06:25:36 | Information | Updated contact from Google to Outlook: "LRedacted".
2025-10-17 06:25:37 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:25:38 | Information | Updated contact from Google to Outlook: "NRedacted".
2025-10-17 06:25:38 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:25:39 | Information | Updated contact from Google to Outlook: "DRedacted".
2025-10-17 06:25:40 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:25:41 | Information | Updated contact from Google to Outlook: "RRedacted".
2025-10-17 06:25:42 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:25:43 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:25:43 | Information | Updated contact from Google to Outlook: "CRedacted".
2025-10-17 06:25:44 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:25:45 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:25:46 | Information | Updated contact from Google to Outlook: "VRedacted".
2025-10-17 06:25:47 | Information | Updated contact from Google to Outlook: "PRedacted".
2025-10-17 06:25:47 | Information | Updated contact from Google to Outlook: "GRedacted".
2025-10-17 06:25:48 | Information | Updated contact from Google to Outlook: "DRedacted".
2025-10-17 06:25:49 | Information | Updated contact from Google to Outlook: "JRedacted".
2025-10-17 06:25:50 | Information | Updated contact from Google to Outlook: "FRedacted".
2025-10-17 06:25:51 | Information | Updated contact from Google to Outlook: "BRedacted".
2025-10-17 06:25:52 | Information | Updated contact from Google to Outlook: "GRedacted".
2025-10-17 06:25:52 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:25:53 | Information | Updated contact from Google to Outlook: "BRedacted".
2025-10-17 06:25:54 | Information | Updated contact from Google to Outlook: "WRedacted".
2025-10-17 06:25:55 | Information | Updated contact from Google to Outlook: "ARedacted".
2025-10-17 06:25:56 | Information | Updated contact from Google to Outlook: "CRedacted".
2025-10-17 06:25:57 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:25:59 | Information | Updated contact from Google to Outlook: "WRedacted".
2025-10-17 06:25:59 | Information | Updated contact from Google to Outlook: "RRedacted".
2025-10-17 06:26:00 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:26:01 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:26:02 | Information | Updated contact from Google to Outlook: "TRedacted".
2025-10-17 06:26:03 | Information | Updated contact from Google to Outlook: "PRedacted".
2025-10-17 06:26:04 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:26:05 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:26:05 | Information | Updated contact from Google to Outlook: "GRedacted".
2025-10-17 06:26:06 | Information | Updated contact from Google to Outlook: "TRedacted".
2025-10-17 06:26:07 | Information | Updated contact from Google to Outlook: "DRedacted".
2025-10-17 06:26:08 | Information | Updated contact from Google to Outlook: "RRedacted".
2025-10-17 06:26:09 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:26:10 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:26:11 | Information | Updated contact from Google to Outlook: "BRedacted".
2025-10-17 06:26:11 | Information | Updated contact from Google to Outlook: "CRedacted".
2025-10-17 06:26:12 | Information | Updated contact from Google to Outlook: "ARedacted".
2025-10-17 06:26:13 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:26:14 | Information | Updated contact from Google to Outlook: "NRedacted".
2025-10-17 06:26:15 | Information | Updated contact from Google to Outlook: "LRedacted".
2025-10-17 06:26:15 | Information | Updated contact from Google to Outlook: "MRedacted".
2025-10-17 06:26:16 | Information | Updated contact from Google to Outlook: "HRedacted".
2025-10-17 06:26:17 | Information | Updated contact from Google to Outlook: "ARedacted".
2025-10-17 06:26:18 | Information | Updated contact from Google to Outlook: "CRedacted".
2025-10-17 06:26:19 | Information | Updated contact from Google to Outlook: "JRedacted".
2025-10-17 06:26:20 | Information | Updated contact from Google to Outlook: "SRedacted".
2025-10-17 06:26:20 | Information | Updated contact from Google to Outlook: "ARedacted".
2025-10-17 06:26:21 | Information | Updated contact from Google to Outlook: "RRedacted".
2025-10-17 06:26:22 | Information | Updated contact from Google to Outlook: "WRedacted".
2025-10-17 06:26:23 | Information | Updated contact from Google to Outlook: "CRedacted".
2025-10-17 06:26:24 | Information | Updated contact from Google to Outlook: "DRedacted".
2025-10-17 06:26:26 | Information | Sync complete. Synced: 67 out of 253. Deleted: 0. Skipped: 0. Errors: 0.**

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Florian Saller - 2026-01-13

status: open --> pending

assigned_to: Florian Saller
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Florian Saller - 2026-01-13

I think I found the reason after several internet searches and trying out: Obviously, the hash algorithm we are using to collapse the Google Account name into an Outlook Property name changed between the .NET Framework 4.7.2 (used in 4.1.x versions and earlier) and 4.8.1 (used in the newer versions). Unfortunately we needed to upgrade to 4.8.1 to be on the Microsoft supported Framework, but there seems to be no backward compliance with the hash algorithm.
Please test the version I released here and let me know, if it works https://sourceforge.net/projects/googlesyncmod/files/Releases/4.1.34%20-%20Branch%20for%20.NET4.7.2%20fixes/

Anyway, I would advice you to upgrade to latest .NET Framework to not oppose your system any security threads. To do so, you should install the latest version (4.2.x), then Reset matches first, before resync (maybe, if possible, delete all entries first on one side, Outlook or Google, and then reset, and then start the sync again to copy over a synched version to the other side again)

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Jason King - 2026-04-04

Post awaiting moderation.

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