https://help.tallysolutions.com/docs/faqs/all_releases/5144.html

Error Tranmgr.900 or Linkmgr.900 or Manager.900

Cause

While selecting a company in Tally.ERP 9, this message appears when data files are corrupted. This message may also appear while opening Tally.ERP 9 when the company with corrupted data is set as the default company.

If you synchronize your Tally.ERP 9 data using the Sync Center in Microsoft Windows, then a conflict might arise between the Tally.ERP 9 data stored on your computer and the data that you have stored online. This conflict in data versions may cause data corruption.

Solution

Back up your existing Tally.ERP 9 data in a location different from the original folder.

· If you have recently taken a backup of your Tally.ERP 9 data, then restore your data.

· If you have not recently taken a backup of your Tally.ERP 9 data, then rewrite your data.

If this error still appears, contact Tally Solutions.

How to prevent this error

· Disable offline files on the server and client computers.

· Ensure that the data folder and other Tally.ERP 9 files are added to the exceptions list of your antivirus and/or MS Windows Defender. For example, if you use Guardian NetSecure antivirus, you can click here for more information. Similarly, you can add Tally.ERP 9 files to the exceptions list of your preferred antivirus.