QB Issue Resolution:
Have you updated the data file to 2015?
Resolution for Issue 'I have lost all data from the 2012 version to the 2015 version. I have tried to restore the file. No change' available: Yes (Solved).
Source: Intuit Community forum.
I have lost all data from the 2012 version to the 2015 version. I have tried to restore the file. No change: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.Support for 2015
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!
Error Recovery for 2015 [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.
Additional Support Options: