Apparently your accountant does not know how to set up Sage 50.  Do not unlink the accounts or you will be out of balance.

You are correct, the historical outstanding purchase invoices need to be entered individually under each vendor's records in the Payables module.  Go to the Historical tab on each Vendor's ledger and enter the outstanding amount of any outstanding Historical invoice.

An accrual entry for $4000 does not typically have a vendor, so I would use the Accrued Liabilities account, not Accounts Payable.

Now, what is Historical?  This is often misunderstood.

Historical is anything that happens before using Sage 50.

How do you set up a file?  Well there are about 5 ways to do it, with some more complicated than others however, the main issue is picking the dates.

Fiscal start and end dates relate to your company fiscal year.  it could be Jan-Dec or May-Apr.

Because you didn't provide the information, I am making assumptions.  Let's assume a fiscal year is Jan-Dec but you are starting your use of Sage 50 on Jul 1.

Of all the ways to set up, I would set up with the fiscal start of Jan 1/18 and End Dec 31/18 with the Earliest transaction date of Jun 30/18.

For this example, I am assuming the Trial Balance you received from the accountant is dated Jun 30/20, the last day you are using the old bookkeeping method.

In this example, there will be Historical outstanding payables invoices and some are likely from the current year Jan 1-Jun 30/28, but none should be dated after Jun 30/18 because that is not Historically Outstanding.  Anything dated Jul 1/18 and later would be entered as normal data entry methods after the file is set up.

Hopefully that will get you going.

Apparently your accountant does not know how to set up Sage 50.  Do not unlink the accounts or you will be out of balance.

You are correct, the historical outstanding purchase invoices need to be entered individually under each vendor's records in the Payables module.  Go to the Historical tab on each Vendor's ledger and enter the outstanding amount of any outstanding Historical invoice.

An accrual entry for $4000 does not typically have a vendor, so I would use the Accrued Liabilities account, not Accounts Payable.

Now, what is Historical?  This is often misunderstood.

Historical is anything that happens before using Sage 50.

How do you set up a file?  Well there are about 5 ways to do it, with some more complicated than others however, the main issue is picking the dates.

Fiscal start and end dates relate to your company fiscal year.  it could be Jan-Dec or May-Apr.

Because you didn't provide the information, I am making assumptions.  Let's assume a fiscal year is Jan-Dec but you are starting your use of Sage 50 on Jul 1.

Of all the ways to set up, I would set up with the fiscal start of Jan 1/18 and End Dec 31/18 with the Earliest transaction date of Jun 30/18.

For this example, I am assuming the Trial Balance you received from the accountant is dated Jun 30/20, the last day you are using the old bookkeeping method.

In this example, there will be Historical outstanding payables invoices and some are likely from the current year Jan 1-Jun 30/28, but none should be dated after Jun 30/18 because that is not Historically Outstanding.  Anything dated Jul 1/18 and later would be entered as normal data entry methods after the file is set up.

Hopefully that will get you going.