Confused: message error finished with errors but valid copy Acronis Home 2014

I use Acronis T! 2014 Premium with Win7. For a year I have been using a Drobo as my backup device without a problem. Recently, I receive an error message that the backup completed with errors but when I run Validate, the archive is valid. What might be the issue?

Thanks
Ken K

Here is the notification that was emailed to me...
1 Information 12/15/2014 11:03:01 PM Backup reserve copy attributes: format tib; need_reserve_backup_copy false;
2 Information 12/15/2014 11:03:01 PM Operation Thunderbird started by schedule.
3 Information 12/15/2014 11:03:01 PM Operation description: Stage Description.
4 Information 12/15/2014 11:03:11 PM Backup reserve copy attributes: format tib; need_reserve_backup_copy false;
5 Information 12/15/2014 11:03:11 PM Priority changed to Low.
6 Information 12/15/2014 11:03:12 PM Create Backup Archive From: E:\Thunderbird\
To file: "Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1.tib" Compression: Normal Exclude: System files
7 Information 12/15/2014 11:03:14 PM Writing full version to file: Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1.tib
8 Information 12/15/2014 11:18:45 PM The following backups have been successfully created: "\\Drobo5N\Public\BACKUPS\Email\Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1.tib"
9 Information 12/15/2014 11:18:46 PM Validate Backup Archive Location: "\\Drobo5N\Public\BACKUPS\Email\Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1.tib"
10 Information 12/15/2014 11:27:38 PM Consolidate Backup Archive Location: "\\Drobo5N\Public\BACKUPS\Email\Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1.tib" Destination: "\\Drobo5N\Public\BACKUPS\Email\Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1_C178F9E6-598C-4C6A-8040-605B8E1E146B.tib"
11 Information 12/15/2014 11:27:38 PM Consolidate Backup Archive Location: "\\Drobo5N\Public\BACKUPS\Email\Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1.tib" Destination: "\\Drobo5N\Public\BACKUPS\Email\Thunderbird2014-12-15WIN7Thunderbird33_full_b5_s1_v1_C178F9E6-598C-4C6A-8040-605B8E1E146B.tib"
12 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
13 True Image 12/15/2014 11:27:39 PM Error occurred while opening the file.
14 True Image 12/15/2014 11:27:39 PM The system cannot find the path specified
15 True Image 12/15/2014 11:27:39 PM Failed to open data stream. Try to remove the backup from the list, add it again by clicking 'Browse for backup' and recreate the backup settings.
16 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
17 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
18 True Image 12/15/2014 11:27:39 PM Error occurred while opening the file.
19 True Image 12/15/2014 11:27:39 PM The system cannot find the path specified
20 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
21 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
22 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
23 True Image 12/15/2014 11:27:39 PM Failed to exclusively access backup Z:\BACKUPS\Email\Thunderbird2014-11-24WIN7Thunderbird13_inc_b2_s5_v1.tib during consolidation. Make sure the backup file is not opened in other applications.
24 True Image 12/15/2014 11:27:39 PM Error occurred while opening the file.
25 True Image 12/15/2014 11:27:39 PM The system cannot find the path specified
26 True Image 12/15/2014 11:27:39 PM Operation has completed with errors.