There is a way you can work around this problem. Transactions can be imported into a closed year. Here's how you can do it.

1. MAKE A BACKUP - Do not skip this step. There is no way to undo this process other than restoring a backup.
2. Make the needed adjusting entries but post them to a current date. It makes things a little easier if you pick a date with no other transactions.
3. Go to the File menu and choose Select Import/Export
4. Export the transactions you just entered. Assuming they were general journal entries, select General Ledger on the left and then General Journal from the list on the right. Click the Export button. Set filters so that you only export the adjusting entries. Go to the Options tab and check the "Include Headings" box. You can also change the file name and location but the default is usually fine.
5. Delete the entries you made in step 2.
6. Locate the file you exported in step 4 and open it in Excel. Change the transaction dates to the date you want for the adjusting entries.
7. Save the file. Do not change it to another format, leave it as a CSV file.
8. Import the file into Sage 50. Go back to Select Import/Export and select General Journal again but this time select the Import button. Go to the Options tab and check the "First row contains Headings" box. If you changed the file name or location, select the correct file before hitting OK.
9. When the import finishes, check to make sure everything imported correctly. There is no way to edit or delete entries in a closed year. So if the results were not what you wanted, you must restore the backup you made at the beginning of this process.