What version and build of Moneydance are you running, e.g. 2019.4(1892)?
What devices are you syncing, computers, mobile devices, phones etc. What are the computers operating system.
With this information i could post a sync reset procedure which would get rid of most of the mdtxn files.
The best way forward is to reset syncing as follows.
When you sync you have one primary computer, syncing set up under FILE (MONEYDANCE on Mac) -SYNCING and one or more secondary computer, syncing set up under FILE (MONEYDANCE on Mac) - NEW – SYNC – OPEN SYNCED FILE. Make sure your data set on your primary computer is up to date, all transactions synced.
1. If you have mobile devices use their setting menu to disconnect.
2. Set primary computer “Sync Method” to “Don’t Sync” under FILE (MONEYDANCE on Mac) – SYNCING, then click OK.
3. On your primary computer use FILE (MONEYDANCE on Mac) – EXPORT BACKUP to save a backup in case something goes wrong.
4. If you have a one or more secondary computers on each click on HELP (MONEYDANCE on Mac) – SHOW DOCUMENT FOLDER to open a file explorer, close Moneydance and delete your second computers data sets “yourdatasetname.moneydance”.
5. Assuming you have Dropbox client installed using your primary computer in the Dropbox folder delete the folder “.moneydancesync”. Watch the Dropbox icon and wait till it states “Up to Date”. This can talk some time. Note on Mac “.moneydancesync” is hidden, try in your Finder window, typing CMD-Shift-G and then pasting ~/Dropbox/.moneydancesync/ into the box to unhide.
6. If you have one or more secondary computers check that in the Dropbox folder that the folder “.moneydancesync” has been automatically deleted. You need to give Dropbox a short time to complete this deletion.
7. On your primary computer under FILE - SYNCING, set your “Encryption Passphrase”, set “Sync Method” to “Dropbox Folder”, click OK.
8. Wait for Dropbox folder “.moneydancesync” and its contents to be created. Check the Dropbox icon states “Up to Date”. This can take some time.
9. If you don’t have one or more secondary computers skip to step 18.
10. On each of your second computers wait until the same Dropbox folder appears, again watch the Dropbox icon this time on your secondary computers and wait till it states “Up to Date”.
11. On each or your secondary computers starting Moneydance should open it in the welcome window, click on “Create a new account set”.
12. Select “Open Synced File” and use dropdown to select “Dropbox Folder” then click NEXT.
13. You should see a search screen headed “Select a synced document to open”
14. After a short search delay, it should then list your un-synced data set name used on your primary computer.
15. Highlight your data set name and click NEXT.
16. Enter the encryption password, the “Encryption Passphrase” you set on your primary computer under FILE – SYNCING.
17. Then click on FINISH. Wait for your data to be synced.
You may find a lot of old, maybe closed accounts or other accounts you have removed from the side bar reappearing in the second computers side bar. Use the “+” sign at bottom of side bar then ADVANCED to tidy up the side bar.
18. Then sync your mobile devices as outlined https://infinitekind.tenderapp.com/kb/syncing-and-sharing-data/sync...